1
|
de Oliveira HT, Couto GK, Davel AP, Xavier FE, Rossoni LV. Chronic cyclooxygenase-2 inhibition prevents the worsening of hypertension and endothelial dysfunction induced by ouabain in resistance arteries of spontaneously hypertensive rats. Vascul Pharmacol 2021; 139:106880. [PMID: 34052431 DOI: 10.1016/j.vph.2021.106880] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/21/2021] [Accepted: 05/25/2021] [Indexed: 01/16/2023]
Abstract
AIM Previous studies raise cyclooxygenase (COX) activation as a possible mechanism involved in the pathophysiology of ouabain-induced hypertension. We hypothesized that inhibition of COX-2 activity might prevent ouabain-induced vascular dysfunction and worsening of hypertension in spontaneously hypertensive rats (SHR). METHODS SHR were exposed to ouabain or vehicle and treated or not with the selective COX-2 inhibitor nimesulide for 5 weeks. Systolic blood pressure was measured by plethysmography. Vascular reactivity by wire myograph and protein expression by Western-blot were assessed in mesenteric resistance arteries (MRA) of groups. Thromboxane A2 (TXA2) production by ELISA was evaluated in MRA supernatants of groups. RESULTS Noradrenaline-induced maximal contraction (Emax) was greater in MRA from SHR receiving ouabain than those of vehicle group. In situ inhibition of COX-2, TXA2 synthase, or TP receptor reduced the Emax to noradrenaline in MRA of ouabain to vehicle levels. TXA2 production was higher in ouabain than in vehicle group. Ouabain enhanced expression of cytoplasmic tyrosine kinase Src (c-Src)/ERK1/2/COX-2/TXA2 synthase/TP receptor in SHR MRA, but did not change NFkB/iKB ratio. Anticontractile effect of nitric oxide (NO) was smaller in MRA from ouabain- than vehicle-treated SHR, as well as eNOS and nNOS expression. Nimesulide co-treatment prevented the ouabain-induced worsening of hypertension and noradrenaline MRA hypercontractility in SHR. CONCLUSION Ouabain worsen hypertension and induce MRA hypercontractility in SHR associated with upregulated c-Src/ERK1/2/COX-2/TXA2 synthase/TXA2/TP receptor axis. These effects were prevented by COX-2 inhibition.
Collapse
Affiliation(s)
- Helane Tito de Oliveira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | - Gisele Kruger Couto
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | - Ana Paula Davel
- Department of Structural and Functional Biology, University of Campinas, Campinas, Brazil
| | - Fabiano Elias Xavier
- Department of Physiology and Pharmacology, Biosciences Center, Federal University of Pernambuco, Recife, Brazil
| | - Luciana Venturini Rossoni
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil.
| |
Collapse
|
2
|
Li L, Bi Z, Hu Y, Sun L, Song Y, Chen S, Mo F, Yang J, Wei Y, Wei X. Silver nanoparticles and silver ions cause inflammatory response through induction of cell necrosis and the release of mitochondria in vivo and in vitro. Cell Biol Toxicol 2021; 37:177-191. [PMID: 32367270 DOI: 10.1007/s10565-020-09526-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 04/06/2020] [Indexed: 02/05/2023]
Abstract
Owing to the excellent antibacterial and antiviral activity, silver nanoparticles have a widespread use in the food and pharmaceutical industries. With the increase in the production and use of the related products, the potential hazard of silver nanoparticles has aroused public attention. The main purpose of this study is to explore the toxicity of silver nanoparticles and induction of lung inflammation in vitro and in vivo. Here, we validated that small amounts of silver ions dissolved from silver nanoparticles caused the depolarization of plasma membrane, resulting in an overload of intracellular sodium and calcium, and eventually led to the cell necrosis. The blockers of calcium or sodium channels inversed the toxicity of silver ions. Then, we instilled silver nanoparticles or silver nitrate (50 μg per mouse) into the lungs of mice, and this induced pulmonary injury and mitochondrial content release, led to the recruitment of neutrophils to the lung tissue via p38 MAPK pathway. Altogether, these data show that released silver ions from nanoparticles induced cell necrosis through Na+ and Ca2+ influx and triggered pulmonary inflammation through elevating mitochondrial-related contents released from these necrotic cells.
Collapse
Affiliation(s)
- Lu Li
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Zhenfei Bi
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yuzhu Hu
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Lu Sun
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yanlin Song
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Siyuan Chen
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Fei Mo
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Jingyun Yang
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yuquan Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China
| | - Xiawei Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, Sichuan, 610041, People's Republic of China.
| |
Collapse
|
3
|
Leite JA, Isaksen TJ, Heuck A, Scavone C, Lykke-Hartmann K. The α 2 Na +/K +-ATPase isoform mediates LPS-induced neuroinflammation. Sci Rep 2020; 10:14180. [PMID: 32843655 PMCID: PMC7447643 DOI: 10.1038/s41598-020-71027-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022] Open
Abstract
Na+/K+-ATPase is a transmembrane ion pump that is essential for the maintenance of ion gradients and regulation of multiple cellular functions. Na+/K+-ATPase has been associated with nuclear factor kappa B (NFκB) signalling, a signal associated with lipopolysaccharides (LPSs)-induced immune response in connection with activated Toll-like receptor 4 (TLR4) signalling. However, the contribution of Na+/K+-ATPase to regulating inflammatory responses remains elusive. We report that mice haploinsufficient for the astrocyte-enriched α2Na+/K+-ATPase isoform (α2+/G301R mice) have a reduced proinflammatory response to LPS, accompanied by a reduced hypothermic reaction compared to wild type litter mates. Following intraperitoneal injection of LPS, gene expressions of Tnf-α, Il-1β, and Il-6 was reduced in the hypothalamus and hippocampus from α2+/G301R mice compared to α2+/+ littermates. The α2+/G301R mice experienced increased expression of the gene encoding an antioxidant enzyme, NRF2, in hippocampal astrocytes. Our findings indicate that α2Na+/K+-ATPase haploinsufficiency negatively modulates LPS-induced immune responses, highlighting a rational pharmacological target for reducing LPS-induced inflammation.
Collapse
Affiliation(s)
- J A Leite
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Pharmacology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil.,Department of Pharmacology, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - T J Isaksen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - A Heuck
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - C Scavone
- Department of Pharmacology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - K Lykke-Hartmann
- Department of Biomedicine, Aarhus University, Aarhus, Denmark. .,Department of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark. .,Department of Clinical Genetics, Aarhus University Hospital, 8200, Aarhus N, Denmark.
| |
Collapse
|
4
|
Paul D, Soignier RD, Minor L, Tau H, Songu-Mize E, Gould HJ. Regulation and pharmacological blockade of sodium-potassium ATPase: a novel pathway to neuropathy. J Neurol Sci 2014; 340:139-43. [PMID: 24661409 DOI: 10.1016/j.jns.2014.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/20/2014] [Accepted: 03/06/2014] [Indexed: 10/25/2022]
Abstract
Inflammation causes upregulation of NaV1.7 sodium channels in the associated dorsal root ganglia (DRG). The resultant increase in sodium influx must be countered to maintain osmotic homeostasis. The primary mechanism to pump sodium out of neurons is Na(+), K(+)-ATPase. To test whether there is a compensatory upregulation of Na(+), K(+)-ATPase after inflammation, rats received an injection of complete Freund's adjuvant (CFA) into one hindpaw and saline into the contralateral hindpaw. Three days later, L4-L6 DRGs were extracted and analyzed using gel electrophoresis and immunohistochemistry. Immunoreactivity for both the α-1 and α-3 subunits were increased in DRG associated with CFA-treatment, compared to saline-treatment. To test whether dysregulation of Na(+), K(+)-ATPase may cause cell death after inflammation, we produced a pharmacological blockade with ouabain (10mg/kg, s.c.) three days after CFA injection and paws were stimulated or not. Twenty-four hours later, DRG were removed and stained with cresyl violet. Greater cell death was seen in DRG from ouabain-treated animals on the CFA treated side than the saline-treated side. Paw stimulation doubled this difference. Control DRG showed little neuronal death. These results are evidence that regulation of Na(+), K(+)-ATPase during major inflammatory disease states is critical for homeostatic protection of primary afferent neurons.
Collapse
Affiliation(s)
- Dennis Paul
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA 70112, United States; Department of Neurology, LSU Health Sciences Center, New Orleans, LA 70112, United States; Department of Anesthesiology, LSU Health Sciences Center, New Orleans, LA 70112, United States; Department of Physical Medicine and Rehabilitation, LSU Health Sciences Center, New Orleans, LA 70112, United States; Neuroscience Center of Excellence, LSU Health Sciences Center, New Orleans, LA 70112, United States; Center of Excellence for Oral and Craniofacial Biology, LSU Health Sciences Center, New Orleans, LA 70112, United States; Alcohol and Drug Abuse Center of Excellence, LSU Health Sciences Center, New Orleans, LA 70112, United States.
| | - R Denis Soignier
- Department of Neurology, LSU Health Sciences Center, New Orleans, LA 70112, United States; Neuroscience Center of Excellence, LSU Health Sciences Center, New Orleans, LA 70112, United States
| | - Lerna Minor
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA 70112, United States
| | - Hui Tau
- Department of Neurology, LSU Health Sciences Center, New Orleans, LA 70112, United States
| | - Emel Songu-Mize
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA 70112, United States; Neuroscience Center of Excellence, LSU Health Sciences Center, New Orleans, LA 70112, United States
| | - Harry J Gould
- Department of Neurology, LSU Health Sciences Center, New Orleans, LA 70112, United States; Department of Anesthesiology, LSU Health Sciences Center, New Orleans, LA 70112, United States; Department of Physical Medicine and Rehabilitation, LSU Health Sciences Center, New Orleans, LA 70112, United States; Neuroscience Center of Excellence, LSU Health Sciences Center, New Orleans, LA 70112, United States; Center of Excellence for Oral and Craniofacial Biology, LSU Health Sciences Center, New Orleans, LA 70112, United States
| |
Collapse
|
5
|
Ribeiro Junior RF, Fernandes AA, Meira EF, Batista PR, Siman FDM, Vassallo DV, Padilha AS, Stefanon I. Soybean oil increases SERCA2a expression and left ventricular contractility in rats without change in arterial blood pressure. Lipids Health Dis 2010; 9:53. [PMID: 20504316 PMCID: PMC2894821 DOI: 10.1186/1476-511x-9-53] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 05/26/2010] [Indexed: 01/08/2023] Open
Abstract
Background Our aim was to evaluate the effects of soybean oil treatment for 15 days on arterial and ventricular pressure, myocardial mechanics and proteins involved in calcium handling. Methods Wistar rats were divided in two groups receiving 100 μL of soybean oil (SB) or saline (CT) i.m. for 15 days. Ventricular performance was analyzed in male 12-weeks old Wistar rats by measuring left ventricle diastolic and systolic pressure in isolated perfused hearts according to the Langendorff technique. Protein expression was measured by Western blot analysis. Results Systolic and diastolic arterial pressures did not differ between CT and SB rats. However, heart rate was reduced in the SB group. In the perfused hearts, left ventricular isovolumetric systolic pressure was higher in the SB hearts. The inotropic response to extracellular Ca2+ and isoproterenol was higher in the soybean-treated animals than in the control group. Myosin ATPase and Na+-K+ATPase activities, the expression of sarcoplasmic reticulum calcium pump (SERCA2a) and sodium calcium exchanger (NCX) were increased in the SB group. Although the phosfolamban (PLB) expression did not change, its phosphorylation at Ser16 was reduced while the SERCA2a/PLB ratio was increased. Conclusions In summary, soybean treatment for 15 days in rats increases the left ventricular performance without affecting arterial blood pressure. These changes might be associated with an increase in the myosin ATPase activity and SERCA2a expression.
Collapse
|
6
|
Krishnamoorthy RR, Prasanna G, Dauphin R, Hulet C, Agarwal N, Yorio T. Regulation of Na,K-ATPase expression by endothelin-1 in transformed human ciliary non-pigmented epithelial (HNPE) cells. J Ocul Pharmacol Ther 2004; 19:465-81. [PMID: 14583138 DOI: 10.1089/108076803322473024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Endothelin-1 (ET-1) (1-100 nM) decreases the activity of Na,K-ATPase, a key enzyme responsible for aqueous humor formation, in transformed human non-pigmented ciliary epithelial (HNPE) cells. The present study sought to determine if ET-1 alters the expression of the catalytically active alpha subunit of Na,K-ATPase in HNPE cells and identify mechanisms underlying these effects. We report that acute (15 and 30 min) treatment with ET-1 results in an increase in mRNA expression of the alpha 1 subunit of Na,K-ATPase. Similar to ET-1's effects, ouabain (100 microM), a selective inhibitor of Na,K-ATPase, and monensin (10 microM), a sodium ionophore, also increased Na,K-ATPase expression in HNPE cells. The increase in Na,K-ATPase expression by short-term treatment with ouabain and monensin was dependent on their ability to elevate intracellular sodium concentrations. However, acute ET-1 treatment mediated increase in Na,K-ATPase expression was independent of changes in intracellular sodium. A prolonged (24 hr) ET-1 treatment results in an increase in both mRNA and protein levels of the alpha 1 subunit of Na,K-ATPase. These observations suggest that ET-1 could play a homeostatic role in modulating aqueous humor formation by having differential effects on the activity and expression of Na,K-ATPase by the ciliary epithelium in the eye.
Collapse
Affiliation(s)
- Raghu R Krishnamoorthy
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
| | | | | | | | | | | |
Collapse
|
7
|
Despa S, Islam MA, Pogwizd SM, Bers DM. Intracellular [Na+] and Na+ pump rate in rat and rabbit ventricular myocytes. J Physiol 2002; 539:133-43. [PMID: 11850507 PMCID: PMC2290132 DOI: 10.1113/jphysiol.2001.012940] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Intracellular [Na+] ([Na+]i) is centrally involved in regulation of cardiac Ca2+ and contractility via Na+-Ca2+ exchange (NCX) and Na+-H+ exchange (NHX). Previous work has indicated that [Na+]i is higher in rat than rabbit ventricular myocytes. This has major functional consequences, but the reason for the higher [Na+]i in rat is unknown. Here, resting [Na+]i was measured using the fluorescent indicator SBFI, with both traditional calibration and a novel null-point method (which circumvents many limitations of prior methods). In rabbit, resting [Na+]i was 4.5 +/- 0.4 mM (traditional calibration) and 4.4 mM (null-point). Resting [Na+]i in rat was significantly higher using both the traditional calibration (11.1 +/- 0.7 mM) and the null-point approach (11.2 mM). The rate of Na+ transport by the Na+ pump was measured as a function of [Na+]i in intact cells. Rat cells exhibited a higher V(max) than rabbit (7.7 +/- 1.1 vs. 4.0 +/- 0.5 mM x min(-1)) and a higher K(m) (10.2 +/- 1.2 vs. 7.5 +/- 1.1 mM). This results in little difference in pump activity for a given [Na+]i below 10 mM, but at measured resting [Na+]i levels the pump-mediated Na+ efflux is much higher in rat. Thus, Na+ pump rate cannot explain the higher [Na+]i in rat. Resting Na+ influx rate was two to four times higher in rat, and this accounts for the higher resting [Na+]i. Using tetrodotoxin, HOE-642 and Ni2+ to block Na+ channels, NHX and NCX, respectively, we found that all three pathways may contribute to the higher resting Na+ influx in rat (albeit differentially). We conclude that resting [Na+]i is higher in rat than in rabbit, that this is caused by higher resting Na+ influx in rat and that a higher Na+,K+-ATPase pumping rate in rat is a consequence of the higher [Na+]i.
Collapse
Affiliation(s)
- Sanda Despa
- Department of Physiology and Cardiovascular Institute, Loyola University Chicago, Maywood, IL 60153, USA
| | | | | | | |
Collapse
|
8
|
Rossoni LV, Salaices M, Marín J, Vassallo DV, Alonso MJ. Alterations in phenylephrine-induced contractions and the vascular expression of Na+,K+-ATPase in ouabain-induced hypertension. Br J Pharmacol 2002; 135:771-81. [PMID: 11834625 PMCID: PMC1573170 DOI: 10.1038/sj.bjp.0704501] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2001] [Revised: 11/13/2001] [Accepted: 11/13/2001] [Indexed: 11/09/2022] Open
Abstract
Hypertension development, phenylephrine-induced contraction and Na(+),K(+)-ATPase functional activity and protein expression in aorta (AO), tail (TA) and superior mesenteric (SMA) arteries from ouabain- (25 microg day(-1), s.c., 5 weeks) and vehicle-treated rats were evaluated. Ouabain treatment increased systolic blood pressure (127+/-1 vs 160+/-2 mmHg, n=24, 35; P<0.001) while the maximum response to phenylephrine was reduced (P<0.01) in AO (102.8+/-3.9 vs 67.1+/-10.1% of KCl response, n=12, 9) and SMA (82.5+/-7.5 vs 52.2+/-5.8%, n=12, 9). Endothelium removal potentiated the phenylephrine response to a greater extent in segments from ouabain-treated rats. Thus, differences of area under the concentration-response curves (dAUC) in endothelium-denuded and intact segments for control and ouabain-treated rats were, respectively: AO, 56.6+/-9.6 vs 198.3+/-18.3 (n=9, 7); SMA, 85.5+/-15.4 vs 165.4+/-24.8 (n=6, 6); TA, 13.0+/-6.1 vs 39.5+/-10.4% of the corresponding control AUC (n=6, 6); P<0.05. The relaxation to KCl (1 - 10 mM) was similar in segments from both groups. Compared to controls, the inhibition of 0.1 mM ouabain on KCl relaxation was greater in AO (dAUC: 64.8+/-4.6 vs 84.0+/-5.1%, n=11, 14; P<0.05), similar in SMA (dAUC: 39.1+/-3.9 vs 43.3+/-7.8%, n=6, 7; P>0.05) and smaller in TA (dAUC: 62.1+/-5.5 vs 41.4+/-8.2%, n=12, 13; P<0.05) in ouabain-treated rats. Protein expression of both alpha(1) and alpha(2) isoforms of Na(+),K(+)-ATPase was augmented in AO, unmodified in SMA and reduced in TA from ouabain-treated rats. These results suggest that chronic administration of ouabain induces hypertension and regional vascular alterations, the latter possibly as a consequence of the hypertension.
Collapse
Affiliation(s)
- Luciana V Rossoni
- Department of Pharmacology and Therapeutics, Facultad de Medicina, Universidad Autónoma de Madrid, Spain
| | | | | | | | | |
Collapse
|
9
|
Sevieux N, Alam J, Songu-Mize E. Effect of cyclic stretch on α-subunit mRNA expression of Na+-K+-ATPase in aortic smooth muscle cells. Am J Physiol Cell Physiol 2001; 280:C1555-60. [PMID: 11350750 DOI: 10.1152/ajpcell.2001.280.6.c1555] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously demonstrated that protein expression of both α1- and α2-catalytic subunits of the Na+-K+-ATPase is elevated after a 2- to 4-day chronic cyclic stretch regimen in cultured aortic smooth muscle cells (ASMC). In the present study, we investigated whether cyclic stretch affects mRNA expression of the α-isoforms of the Na+-K+-ATPase. Using a stretch apparatus, rat ASMC were cyclically stretched 10 or 20% of their length for 1, 3, or 6 h. α-Isoform mRNA levels were measured using Northern analysis. A 3-h 10% stretch had no significant affect on mRNA expression for either isoform, but a 20% stretch increased mRNA of both isoforms approximately twofold. Whereas a 6-h 20% stretch increased α1 mRNA by 3.3-fold, α2 was not affected any further. Actinomycin D blocked the stretch-induced stimulation of mRNA expression of both α-subunits. In conclusion, cyclic stretch stimulates the mRNA expression of both α1- and α2-subunits of Na+-K+-ATPase. The sensitivity of the two genes to the degree and duration of stretch is different. The stretch-induced increase of mRNA may be a result of increased transcription.
Collapse
MESH Headings
- Animals
- Aorta/cytology
- Blotting, Northern
- Cells, Cultured
- Dactinomycin/pharmacology
- Gadolinium/pharmacology
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/physiology
- Hypertension/metabolism
- Hypertension/physiopathology
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/enzymology
- Nucleic Acid Synthesis Inhibitors/pharmacology
- RNA, Messenger/analysis
- Rats
- Rats, Sprague-Dawley
- Sodium-Potassium-Exchanging ATPase/genetics
- Sodium-Potassium-Exchanging ATPase/metabolism
- Stress, Mechanical
- Transcription, Genetic/physiology
Collapse
Affiliation(s)
- N Sevieux
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | | | | |
Collapse
|
10
|
Abstract
The Na(+) pump and its regulation is important for maintaining membrane potential and transmembrane Na(+) gradient in all mammalian cells and thus is essential for cell survival and function. Vascular smooth muscle cells (VSMC) have a relatively low number of pump sites on their membrane compared with other cells. We wished to determine the mechanisms for regulating the number of pump sites in these cells. We used canine saphenous vein VSMC cultured in 10% serum and passaged one time. These cells were subcultured in 5% serum media with low K(+) (1 mM vs. control of 5 mM), and their pump expression was assessed. These VSMC upregulated their pump sites as early as 4 h after treatment (measured by [(3)H]ouabain binding). At this early time point, there was no detectable increase in protein expression of either alpha(1)- or beta(1)-subunits of the pump shown by Western blots. When the cells were treated with the phosphoinositide 3-kinase (PI-3-K) inhibitor LY-294002 (which is known to inhibit cytoplasmic transport processes) in low-K(+) media, the pump site upregulation was inhibited. These data suggest that the low-K(+)-induced upregulation of Na(+) pump number can occur by translocation of preformed pumps from intracellular stores.
Collapse
Affiliation(s)
- A Aydemir-Koksoy
- Cardiovascular Sciences Section, Department of Molecular Physiology, Baylor College of Medicine, Houston, Texas 77030, USA
| | | |
Collapse
|
11
|
Wang W, Okamoto K, Rounds J, Chambers E, Jacobs DO. In vitro complement activation favoring soluble C5b-9 complex formation alters myocellular sodium homeostasis. Surgery 2001; 129:209-19. [PMID: 11174714 DOI: 10.1067/msy.2001.110218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Deranged Na(+) homeostasis in skeletal muscle is closely associated with excessive complement activation that is encountered during sepsis. Recent evidence suggests that soluble C5b-9 complexes (SC5b-9), which are readily detected in plasma during sepsis and have long been considered irrelevant nonmembrane binding end products of complement activation, may have numerous biologic effects. The purpose of this study, therefore, was to determine the effects of SC5b-9 on myocellular ion homeostasis and its mechanism(s) of action. METHODS Hindlimb fast-twitch extensor digitorum longus (EDL) was freshly isolated from rats weighing 50 to 70 g and then incubated at 30 degrees C for 60 minutes in normal Krebs-Henseleit buffer (KHB, pH 7.4) containing 10% zymosan-activated rat serum (10 mg/mL at 37 degrees C for 60 minutes) as a source of SC5b-9. Zymosan particles were removed by centrifugation after activation to exclude any noncomplement direct effects. Heat-inactivated rat serum (56 degrees C for 30 minutes) was used as control. EDL muscle was also incubated with pertussis toxin (1 microg/mL), in Ca(2+)-free KHB, with thapsigargin (0.3 or 3 micromol/L), or with ouabain (0.01, 0.1 or 1 micromol/L) before and/or during incubation with 10% zymosan-activated or heat-inactivated rat serum. Intracellular Na(+) and K(+) contents ([Na(+)](i) or [K(+)](i)) of EDL muscle were determined by using flame photometry after washing in ice-cold Na(+)-free Tris-sucrose buffer. SC5b-9 in zymosan-activated human serum was determined by SC5b-9 enzyme-linked immunoassay. RESULTS SC5b-9 in zymosan-activated human serum significantly increased by 400% as compared with nonactivated, normal human serum. Zymosan-activated rat serum markedly increased [Na+]i without affecting [K(+)](i) in fast-twitch EDL muscle, which was completely inhibited by pertussis toxin, removal of extracellular Ca(2+) or depletion of intracellular Ca(2+) with thapsigargin. The addition of ouabain (at micromolar concentrations) increased myocellular [Na(+)](i) and decreased myocellular [K(+)](i) in both the zymosan-activated and the heat-inactivated rat serum groups. The effects of ouabain on myocellular [Na(+)](i) and [K(+)](i) were equivalent in these 2 groups. Zymosan-activated and heat-inactivated rat serum had similar effects on myocellular [K(+)](i) in the presence or absence of pertussis toxin, removal of extracellular Ca(2+) or depletion of intracellular Ca(2+). CONCLUSIONS Zymosan-activated rat serum (presumed SC5b-9 enriched) selectively alters Na(+) homeostasis in isolated fast-twitch skeletal muscle. The mechanisms for such effects may be linked to G-proteins, Ca(2+) flux and Na(+),K(+)-adenosine triphosphatase pump binding site blockade.
Collapse
Affiliation(s)
- W Wang
- Laboratory for Surgical Metabolism and Nutrition, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | | | | |
Collapse
|
12
|
Songu-Mize E, Liu X, Hymel LJ. Effect of Mechanical Strain on Expression of Na+,K+-ATPase α Subunits in Rat Aortic Smooth Muscle Cells. Am J Med Sci 1998. [DOI: 10.1016/s0002-9629(15)40401-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|