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1.
Biochemistry (Mosc) ; 84(11): 1280-1295, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31760918

RESUMO

Maintenance of non-equilibrium Na+ and K+ distribution between cytoplasm and extracellular medium suggests existence of sensors responding with conformational transitions to the changes of these monovalent cations' intracellular concentration. Molecular nature of monovalent cation sensors has been established in Na,K-ATPase, G-protein-coupled receptors, and heat shock proteins structural studies. Recently, it was found that changes in Na+ and K+ intracellular concentration are the key factors in the transcription and translation control, respectively. In this review, we summarize results of these studies and discuss physiological and pathophysiological significance of Na+i,K+i-dependent gene expression regulation mechanism.


Assuntos
Potássio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Sódio/metabolismo , Animais , Cátions Monovalentes/química , Citoplasma/metabolismo , Proteínas de Choque Térmico/metabolismo , Potássio/química , Biossíntese de Proteínas , Sódio/química , Transcrição Genética
2.
Biochemistry (Mosc) ; 84(9): 1085-1092, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31693468

RESUMO

Many motor disorders are associated with depolarization of the membrane of skeletal muscle fibers due to the impaired functioning of Na,K-ATPase. Here, we studied the role of ouabain (specific Na,K-ATPase ligand) and AMP-activated protein kinase (key regulator of muscle metabolism) in the maintenance of muscle electrogenesis; the levels of these endogenous factors are directly related to the motor activity. After 4-day intraperitoneal administration of ouabain (1 µg/kg daily), a hyperpolarization of sarcolemma was registered in isolated rat diaphragm muscles due to an increase in the electrogenic activity of Na,K-ATPase. In acute experiments, addition of nanomolar ouabain concentrations to the bathing solution resulted in the muscle membrane hyperpolarization within 15 min. The effect of ouabain reversed to membrane depolarization with the increase in the external potassium concentration. It is possible that Na,K-ATPase activation by ouabain may be regulated by such factors as specific subcellular location, interaction with molecular partners, and changes in the ionic balance. Preventive administration of the AMP-activated protein kinase activator AICAR (5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranoside; 400 mg/kg body weight daily for 7 days) in chronic experiments resulted in the stabilization of the endplate structure and abolishment of depolarization of the rat soleus muscle membrane caused by the motor activity cessation. The obtained data can be useful for creating approaches for correction of muscle dysfunction, especially at the early stages, prior to the development of muscle atrophy.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Potenciais de Ação/efeitos dos fármacos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Ouabaína/administração & dosagem , Ouabaína/farmacologia , Aminoimidazol Carboxamida/administração & dosagem , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Animais , Relação Dose-Resposta a Droga , Injeções Intraperitoneais , Masculino , Fibras Musculares Esqueléticas/enzimologia , Fibras Musculares Esqueléticas/metabolismo , Ratos , Ratos Wistar , Ribonucleotídeos/administração & dosagem , Ribonucleotídeos/farmacologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Relação Estrutura-Atividade
3.
Cell Physiol Biochem ; 53(3): 518-531, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31502430

RESUMO

BACKGROUND/AIMS: Liver regeneration is induced by S1P and accompanied with an increase in hepatic Na+/K+ ATPase activity, suggesting a potential modulatory role of the sphingolipid on the ATPase activity. The ability of S1P to alter the ATPase activity was confirmed in a previous work which showed a time dependent effect, with an inhibition appearing at 15min and a stimulation at two hours. The aim of this work was to investigate if FTY720-P, an analogue of S1P used in the treatment of multiple sclerosis, exerts a similar effect at 2 hours. METHODS: HepG2 cells were treated with FTY720-P for two hours and the activity of the Na+/K+ ATPase was assayed by measuring the amount of inorganic phosphate liberated in presence and absence of ouabain. The involvement of NF-κB in the pathway was investigated by determining changes in the protein expression of IκB. RESULTS: FTY720-P induced a 2.5-fold increase in the activity of the Na+/K+ ATPase which was maintained in the presence of JTE-013, a specific blocker of S1PR2, but disappeared completely in presence of CAY 10444, a specific S1PR3 antagonist. The involvement of S1PR3 was supported by the stimulation observed with Cym5541, a S1PR3 agonist. FTY720-P increased the expression of COX2, and reduced that of IκB. Its effect was not manifested in presence of indomethacin, a COX inhibitor, or in presence of an NF-κB inhibitor. Exogenous PGE2 induced a significant stimulatory effect. Inhibiting PKC and ERK with respectively calphostin C and PD98059 abolished the effect of FTY720-P on the ATPase and on IκB, but not that of exogenous PGE2 indicating that the two kinases are upstream of NF-κB and PGE2. The PKC activator PMA increased the activity of the Na+/K+ ATPase as well as the expression of phopho-ERK, inferring that PKC is upstream of ERK. CONCLUSION: It was concluded that FTY720-P stimulates the Na+/K+ ATPase via PGE2 by activating sequentially S1PR3, PKC, ERK, NF-κB. The latter enhances COX-2 expression leading to PGE2 release.


Assuntos
Dinoprostona/metabolismo , Organofosfatos/farmacologia , Receptores de Lisoesfingolipídeo/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Esfingosina/análogos & derivados , Western Blotting , Ativação Enzimática/efeitos dos fármacos , Células Hep G2 , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , NF-kappa B/metabolismo , Proteína Quinase C/metabolismo , Transdução de Sinais/efeitos dos fármacos , Esfingosina/farmacologia
4.
Nihon Yakurigaku Zasshi ; 154(3): 103-107, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31527358

RESUMO

Digitoxin and digoxin are plant-derived cardiac glycosides. They are Na+,K+-ATPase (sodium pump) inhibitors, and have been used clinically for treatment and prevention of heart failure and various tachycardia. On the other hand, some epidemiological studies showed that digoxin users have a lower cancer risk compared to the non-users, and that cancer patients who had been treated with digoxin face on improvement of their survival. In various in vitro studies, cardiac glycosides at sub-µM concentrations, which have no significant effect on enzymatic and ion-transporting activities of Na+,K+-ATPase, show anti-cancer effects. Na+,K+-ATPase is ubiquitously expressed, so it remains unclear why low concentrations of cardiac glycosides have cancer-specific effects. Recently, we found that the receptor-type Na+,K+-ATPase, which has no pumping activity, is associated with leucine-rich repeat-containing 8 family, member A(LRRC8A), one of the components of volume-regulated anion channel (VRAC), in the membrane microdomains of plasma membrane of cancer cells, and that this crosstalk contributes to the inhibition of the cancer cell growth by sub-µM cardiac glycosides. In this mechanism, cardiac glycosides bind to the receptor-type Na+,K+-ATPase, and then stimulate the production of reactive oxygen species (ROS) via NADPH oxidase. The ROS activate VRAC within the membrane microdomains, thus eliciting anti-proliferative effects. VRAC is ubiquitously expressed, and it is normally activated by cell swelling. However, VRAC is activated by cardiac glycoside without cell swelling. On the other hand, the cardiac glycosides-induced effects were not observed in non-cancer cells. Our findings can partly explain why cardiac glycosides elicit selective effects in cancer cells.


Assuntos
Glicosídeos Cardíacos/farmacologia , Neoplasias/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Canais de Ânion Dependentes de Voltagem/metabolismo , Digoxina/farmacologia , Humanos , Proteínas de Membrana/metabolismo , Espécies Reativas de Oxigênio/metabolismo
5.
An Acad Bras Cienc ; 91(3): e20181330, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508665

RESUMO

Type 1 diabetes (T1D) is the result of the selective destruction of the pancreatic ß-cells by T cells of the immune system. Although spleen is a secondary lymphoid organ, it is also involved in the T1D pathogenesis. However, the alterations in a variety of cellular processes of this disease need to be further understood. We aimed to analyze the benefits of resveratrol, and its complexed form on diabetic complications in the spleen of rats. To this end, we investigated important enzymes of phosphoryl transfer network, and Na+, K+-ATPase activity. Wistar rats were divided into non-diabetic groups: Control, Ethanol, Resveratrol, Hydroxypropyl-ß-cyclodextrin, Resveratrol-hydroxypropyl-ß-cyclodextrin, and diabetic groups with the same treatments. Diabetes was induced by a single dose of 60 mg/kg of streptozocin intraperitoneally, and treatments by intragastric gavage once daily for 60 days. Hyperglycemia reduced creatine kinase activity, which was reversed by the administration of resveratrol. Na+, K+-ATPase activity was greatly affected, but it was reversed by resveratrol and resveratrol-hydroxypropyl-ß-cyclodextrin. This suggest an energetic imbalance in the spleen of diabetic rats, and in case this also occurs in the diabetic patients, it is possible that resveratrol supplementation could be beneficial to the better functioning of the spleen in diabetic patients.


Assuntos
2-Hidroxipropil-beta-Ciclodextrina/farmacologia , Antioxidantes/farmacologia , Diabetes Mellitus Experimental/metabolismo , Resveratrol/farmacologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Baço/metabolismo , Animais , Antioxidantes/metabolismo , Glicemia/análise , Peso Corporal , Creatina Quinase/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Metabolismo Energético/efeitos dos fármacos , Hiperglicemia/metabolismo , Masculino , Tamanho do Órgão , Ratos , Ratos Wistar , Estreptozocina
6.
Cell Physiol Biochem ; 53(4): 638-647, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31556253

RESUMO

BACKGROUND/AIMS: Prolonged hyperosmotic shrinkage evokes expression of osmoprotective genes via nuclear factor NFAT5-mediated pathway and activates Na+ influx via hypertonicity-induced cation channels (HICC). In human umbilical vein endothelial cells (HUVEC) elevation of intracellular sodium concentration ([Na+]i) triggers transcription of dozens of early response genes (ERG). This study examined the role of monovalent cations in the expression of Na+i-sensitive ERGs in iso- and hyperosmotically shrunken HUVEC. METHODS: Cell volume was measured by 3D reconstruction of cell shape and as 14C-urea available space. Intracellular Na+ and K+ content was measured by flame atomic absorption spectrometry. ERG transcription was estimated by RT-PCR. RESULTS: Elevation of medium osmolality by 150 mM mannitol or cell transfer from hypo- to isosmotic medium decreased cell volume by 40-50%. Hyperosmotic medium increased [Na+]i by 2-fold whereas isosmotic shrinkage had no impact on this parameter. Hyperosmotic but not isosmotic shrinkage increased up-to 5-fold the content of EGR1, FOS, ATF3, ZFP36 and JUN mRNAs. Expression of these ERGs triggered by hyperosmotic shrinkage and Na+,K+-ATPase inhibition by 0.1 µM ouabain exhibited positive correlation (R2=0.9383, p=0.0005). Isosmotic substitution of NaCl by N-methyl-D-glucamine abolished an increment of [Na+]i and ERG expression triggered by mannitol addition. CONCLUSION: Augmented expression of ERGs in hyperosmotically shrunken HUVEC is mediated by elevation of [Na+]i.


Assuntos
Tamanho Celular , Sódio/metabolismo , Tamanho Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Proteína 1 de Resposta de Crescimento Precoce/genética , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Meglumina/farmacologia , Ouabaína/farmacologia , Potássio/metabolismo , Cloreto de Sódio/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , ATPase Trocadora de Sódio-Potássio/metabolismo , Tristetraprolina/genética , Tristetraprolina/metabolismo
7.
Aquat Toxicol ; 215: 105283, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31470336

RESUMO

Recent studies have demonstrated that white sturgeon are more sensitive to acute exposure to Cu than rainbow trout (Oncorhynchus mykiss), especially during early life-stages. However, the physiological mechanisms underlying this difference in sensitivity to Cu is not known. In the present study, we first confirmed the higher sensitivity (lower 96 h LC50 values) of white sturgeon to Cu at three different life stages (larva, swim-up, and juvenile) relative to their counterparts in rainbow trout. We also demonstrated that acute exposure to Cu (50 µg/L for 4.5 h) caused a significantly greater reduction in the rate of waterborne Na uptake in white sturgeon relative to that in rainbow trout across all three life-stages. In agreement with this observation, we also found that acute exposure to Cu (20 µg/L for 48 h) elicits a significantly greater decrease in whole body Na level in all life stages of white sturgeon compared to rainbow trout. In contrast, white sturgeon demonstrated a higher or similar level of Cu body burden relative to rainbow trout during acute Cu exposure (20 µg/L for 24 h), thereby indicating that Cu bioaccumulation is not a good indicator of its toxicity in these species. Overall, our study demonstrated that the differences in sensitivity to acute Cu exposure between white sturgeon and rainbow trout can be explained on the basis of differential effects of Cu on Na homeostasis.


Assuntos
Cobre/toxicidade , Peixes/fisiologia , Homeostase/efeitos dos fármacos , Oncorhynchus mykiss/fisiologia , Sódio/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Exposição Ambiental , Dose Letal Mediana , Oncorhynchus mykiss/sangue , ATPases Translocadoras de Prótons/metabolismo , Sódio/sangue , ATPase Trocadora de Sódio-Potássio/metabolismo , Testes de Toxicidade Aguda , Qualidade da Água
8.
An Acad Bras Cienc ; 91(3): e20180395, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432900

RESUMO

The aquatic environment presents daily and/or seasonal variations in dissolved oxygen (DO) levels. Piava faces different DO levels in the water due to its distributional characteristics. The goal of this study was to describe the effects of low DO levels on plasma ion, biochemical and oxidative variables in piava juveniles. Fish were exposed to different DO levels, including 1.0, 2.0, 3.0, 4.0 and 5.0 mg L-1 of DO for 96 h, after which blood and tissue samples (liver, kidney, gill and muscle) were collected. The decrease in DO levels decreased plasma Na+, Cl-, K+ and NH3 levels as well as protein and glycogen levels in the liver, kidney and muscle; increased Na+/K+-ATPase activity in the gills and kidney as well as glucose and ammonia levels in the liver, kidney and muscle; and increased lactate levels in the kidney and muscle. Thiobarbituric acid-reacting substances, catalase and non-protein thiol levels decreased in the tissues of piavas exposed to low DO levels. It is concluded that piava can apparently cope with hypoxic conditions; however, low DO levels are a stressor, and the tolerance of piava to hypoxia involves iono-regulatory, metabolic and oxidative adjustments.


Assuntos
Adaptação Fisiológica/fisiologia , Caraciformes/fisiologia , Estresse Oxidativo/fisiologia , Oxigênio/fisiologia , Animais , Catalase/metabolismo , Caraciformes/metabolismo , Ácido Láctico/metabolismo , Oxigênio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismo
9.
Environ Sci Pollut Res Int ; 26(23): 23442-23452, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31197674

RESUMO

The current study demonstrates oxidative damage and associated neurotoxicity following pH stress in two freshwater carp Labeo rohita and Cirrhinus cirrhosus. Carp (n = 6, 3 replicates) were exposed to four different pH (5.5, 6, 7.5, and 8) against control (pH 6.8 ± 0.05) for 7 days. After completion of treatment, levels of enzymatic (superoxide dismutase [SOD], catalase [CAT], glutathione reductase [GRd]) and non-enzymatic antioxidants (malondialdehyde [MDA], glutathione [GSH]), brain neurological parameters (Na+-K+ATPase, acetylcholinesterase [AcHE], monoamine oxidase [MAO], and nitric oxide [NO]), xanthine oxidase (XO), heat shock proteins (HSP70 and HSP90), and transcription factor NFkB were measured in carp brain. Variation in the pH caused a significant alteration in the glutathione system (glutathione and glutathione reductase), SOD-CAT system, and stress marker malondialdehyde (MDA). Xanthine oxidase was also induced significantly after pH exposure. Brain neurological parameters (MAO, NO, AChE, and Na+-K+ATPase) were significantly reduced at each pH-treated carp group though inhibition was highest at lower acidic pH (5.5). Cirrhinus cirrhosus was more affected than that of Labeo rohita. Molecular chaperon HSP70 expression was induced in all pH-treated groups though such induction was more in acid-stressed fish. HSP90 was found to increase only in acid-stressed carp brain. Expression of NFkB was elevated significantly at each treatment group except for pH 7.5. Finally, both acidic and alkaline pH in the aquatic system was found to disturb oxidative balance in carp brain which ultimately affects the neurological activity in carp. However, acidic environment in the aquatic system was more detrimental than the alkaline system regarding oxidative damage and subsequent neurotoxicity in carp brain.


Assuntos
Encéfalo/metabolismo , Peixes/fisiologia , Estresse Fisiológico/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Carpas/metabolismo , Catalase/metabolismo , Cyprinidae/metabolismo , Água Doce , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Malondialdeído/metabolismo , Oxirredução , Estresse Oxidativo , Alimentos Marinhos , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismo , Xantina Oxidase/metabolismo
10.
Aquat Toxicol ; 213: 105221, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207537

RESUMO

Engineered nanomaterials (ENMs) tend to precipitate in saline waters so the majority of aquatic toxicity studies have focused on freshwaters, where bioavailability is presumed to be higher. Recent studies have illustrated that some ENM formulations are bioavailable and bioactive in salt water and that their effects are more pronounced at the physiological than biochemical level. These findings raise concerns regarding the effects of ENMs on marine organisms. Therefore, our goal was to characterize the effects of polyvinylpyrolidone-functionalized silver ENMs (nAg) on aerobic performance in the killifish (Fundulus heteroclitus), a common euryhaline teleost. Fish were exposed to 80 µg L-1 of 5 nm nAg for 48 h in brackish water (12 ppt) and routine (MO2min) and maximum (MO2max) rates of oxygen consumption were quantified. Silver dissolution was minimal and nAg remained well dispersed in brackish water, with a hydrodynamic diameter of 21.0 nm, compared to 19.3 in freshwater. Both MO2min and MO2max were significantly lower (by 53 and 30%, respectively) in killifish exposed to nAg and a reduction in MO2 variability suggested spontaneous activity was suppressed. Neither gill Na+/K+-ATPase activity, nor various other biochemical markers were affected by nAg exposure. The results illustrate that a common ENM formulation is bioactive in salt water and, as in previous studies on functionalized copper ENMs, that effects are more pronounced at the whole animal than the biochemical level.


Assuntos
Água Doce , Fundulidae/fisiologia , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Testes de Toxicidade , Acetilcolinesterase/metabolismo , Aerobiose , Animais , Metabolismo Basal/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Fundulidae/sangue , Brânquias/efeitos dos fármacos , Brânquias/ultraestrutura , Hidrocortisona/sangue , Fígado/metabolismo , Nanopartículas Metálicas/ultraestrutura , Consumo de Oxigênio/efeitos dos fármacos , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/toxicidade
11.
Cell Physiol Biochem ; 52(6): 1381-1397, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31075189

RESUMO

BACKGROUND/AIMS: Ouabain, a well-known plant-derived toxin, is also a hormone found in mammals at nanomolar levels that binds to a site located in the a-subunit of Na⁺,K⁺-ATPase. Our main goal was to understand the physiological roles of ouabain. Previously, we found that ouabain increases the degree of tight junction sealing, GAP junction-mediated communication and ciliogenesis. Considering our previous results, we investigated the effect of ouabain on adherens junctions. METHODS: We used immunofluorescence and immunoblot methods to measure the effect of 10 nM ouabain on the cellular and nuclear content of E-cadherin, ß-catenin and γ-catenin in cultured monolayers of Marin Darby canine renal cells (MDCK). We also studied the effect of ouabain on adherens junction biogenesis through sequential Ca²âº removal and replenishment. Then, we investigated whether c-Src and ERK1/2 kinases are involved in these responses. RESULTS: Ouabain enhanced the cellular content of the adherens junction proteins E-cadherin, ß-catenin and γ-catenin and displaced ß-catenin and γ-catenin from the plasma membrane into the nucleus. Ouabain also increased the expression levels of E-cadherin and ß-catenin in the plasma membrane after Ca²âº replenishment. These effects on adherens junctions were sensitive to PP2 and PD98059, suggesting that they depend on c-Src and ERK1/2 signaling. The translocation of ß-catenin and γ-catenin into the nucleus was specific because ouabain did not change the localization of the tight junction proteins ZO-1 and ZO-2. Moreover, in ouabain-resistant MDCK cells, which express a Na⁺,K⁺-ATPase α1-subunit with low affinity for ouabain, this hormone was unable to regulate adherens junctions, indicating that the ouabain receptor that regulates adherens junctions is Na⁺,K⁺-ATPase. CONCLUSION: Ouabain (10 nM) upregulated adherens junctions. This novel result supports the proposition that one of the physiological roles of this hormone is the modulation of cell contacts.


Assuntos
Junções Aderentes/efeitos dos fármacos , Ouabaína/farmacologia , Junções Aderentes/metabolismo , Animais , Caderinas/metabolismo , Cálcio/metabolismo , Núcleo Celular/metabolismo , Cães , Células Madin Darby de Rim Canino , Microscopia de Fluorescência , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , ATPase Trocadora de Sódio-Potássio/metabolismo , beta Catenina/metabolismo , gama Catenina/metabolismo , Quinases da Família src/metabolismo
12.
Aquat Toxicol ; 212: 54-69, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31075620

RESUMO

In this era of global climate change, ocean acidification is becoming a serious threat to the marine ecosystem. Despite this, it remains almost unknown how fish will respond to the co-occurrence of ocean acidification with other conventional environmental perturbations typically salinity fluctuation and high ammonia threat. Therefore, the present work evaluated the interactive effects of elevated pCO2, salinity reduction and high environmental ammonia (HEA) on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to seawater (32 ppt), to brackish water (10 ppt) and to hyposaline water (2.5 ppt). Following acclimation to different salinities for at least two weeks, fish were exposed to CO2-induced water acidification representing present-day (control pCO2, 400 µatm, LoCO2) and future (high pCO2, 1000 µatm, HiCO2) sea-surface CO2 level for 3, 7 and 21 days. At the end of each exposure period, fish were challenged with HEA for 6 h (1.18 mM representing 50% of 96 h LC50). Results show that, in response to the individual HiCO2 exposure, fish within each salinity compensated for blood acidosis. Fish subjected to HiCO2 were able to maintain ammonia excretion rate (Jamm) within control levels, suggesting that HiCO2 exposure alone had no impact on Jamm at any of the salinities. For 32 and 10 ppt fish, up-regulated expression of Na+/K+-ATPase was evident in all exposure groups (HEA, HiCO2 and HEA/HiCO2 co-exposed), whereas Na+/K+/2Cl- co-transporter was up-regulated mainly in HiCO2 group. Plasma glucose and lactate content were augmented in all exposure conditions for all salinity regimes. During HEA and HEA/HiCO2, Jamm was inhibited at different time points for all salinities, which resulted in a significant build-up of ammonia in plasma and muscle. Branchial expressions of Rhesus glycoproteins (Rhcg isoforms and Rhbg) were upregulated in response to HiCO2 as well as HEA at 10 ppt, with a more moderate response in 32 ppt groups. Overall, our findings denote that the adverse effect of single exposures of ocean acidification or HEA is exacerbated when present together, and suggests that fish are more vulnerable to these environmental threats at low salinities.


Assuntos
Equilíbrio Ácido-Base/efeitos dos fármacos , Ácidos/química , Amônia/toxicidade , Bass/fisiologia , Oceanos e Mares , Osmorregulação/efeitos dos fármacos , Salinidade , Amônia/sangue , Animais , Bass/sangue , Glicemia/metabolismo , Dióxido de Carbono/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glicoproteínas/metabolismo , Concentração de Íons de Hidrogênio , Íons/sangue , Ácido Láctico/sangue , Músculos/efeitos dos fármacos , Músculos/metabolismo , Análise de Componente Principal , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/toxicidade
13.
J Steroid Biochem Mol Biol ; 191: 105372, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31042565

RESUMO

Cardiotonic steroids such as ouabain are potent inhibitors of the sodium pump and have been widely used for centuries in the treatment of congestive heart failure. In recent decades, however, they have also been identified as hormone-like molecules that trigger signaling cascades of physiological relevance by using the various sodium pump α subunit isoforms as receptors. The murine Leydig cell line MLTC-1 expresses both the ubiquitous, relatively ouabain-insensitive α1 isoform of the sodium pump and the ouabain-sensitive α3 isoform that is normally found in neuronal cells. The physiological relevance of the simultaneous presence of the two isoforms in Leydig cells has not been previously addressed. MLTC-1 Leydig cells contain lipid droplets (LDs) and are capable of progesterone biosynthesis when stimulated by luteinizing hormone (LH). When exposed to low nanomolar concentrations of ouabain, they respond with stimulation of Erk1/2, CREB, and ATF-1 phosphorylation, LD enlargement, and perilipin2 mobilization to the LDs. As a result, progesterone biosynthesis is augmented. Abrogation of α3 isoform expression by siRNA prevents all of the above responses, indicating that it is the hormone/receptor-like interaction of ouabain exclusively with this isoform that triggers the signaling events that normally occur when LH binds to its receptor. Considering that ouabain is produced endogenously and is found in seminal fluid, one can speculate that effects of this substance on germ and somatic cells of the testis might play a role in male reproductive physiology.


Assuntos
Cardiotônicos/farmacologia , Células Intersticiais do Testículo/efeitos dos fármacos , Ouabaína/farmacologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Esteroides/metabolismo , Animais , Vias Biossintéticas/efeitos dos fármacos , Linhagem Celular , Células Intersticiais do Testículo/metabolismo , Masculino , Camundongos , Progesterona/metabolismo , Isoformas de Proteínas/metabolismo
14.
Int J Mol Sci ; 20(9)2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31035668

RESUMO

Adhesion is a crucial characteristic of epithelial cells to form barriers to pathogens and toxic substances from the environment. Epithelial cells attach to each other using intercellular junctions on the lateral membrane, including tight and adherent junctions, as well as the Na+,K+-ATPase. Our group has shown that non-adherent chinese hamster ovary (CHO) cells transfected with the canine ß1 subunit become adhesive, and those homotypic interactions amongst ß1 subunits of the Na+,K+-ATPase occur between neighboring epithelial cells. Ouabain, a cardiotonic steroid, binds to the α subunit of the Na+,K+-ATPase, inhibits the pump activity and induces the detachment of epithelial cells when used at concentrations above 300 nM. At nanomolar non-inhibiting concentrations, ouabain affects the adhesive properties of epithelial cells by inducing the expression of cell adhesion molecules through the activation of signaling pathways associated with the α subunit. In this study, we investigated whether the adhesion between ß1 subunits was also affected by ouabain. We used CHO fibroblasts stably expressing the ß1 subunit of the Na+,K+-ATPase (CHO ß1), and studied the effect of ouabain on cell adhesion. Aggregation assays showed that ouabain increased the adhesion between CHO ß1 cells. Immunofluorescence and biotinylation assays showed that ouabain (50 nM) increases the expression of the ß1 subunit of the Na+,K+-ATPase at the cell membrane. We also examined the effect of ouabain on the activation of signaling pathways in CHO ß1 cells, and their subsequent effect on cell adhesion. We found that cSrc is activated by ouabain and, therefore, that it likely regulates the adhesive properties of CHO ß1 cells. Collectively, our findings suggest that the ß1 subunit adhesion is modulated by the expression levels of the Na+,K+-ATPase at the plasma membrane, which is regulated by ouabain.


Assuntos
Adesão Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Ouabaína/farmacologia , Subunidades Proteicas/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Células CHO , Membrana Celular/metabolismo , Cricetulus , Expressão Gênica , Ligação Proteica , Subunidades Proteicas/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/química , ATPase Trocadora de Sódio-Potássio/genética , Quinases da Família src/metabolismo
15.
BMC Genomics ; 20(1): 418, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31126236

RESUMO

BACKGROUND: To control the osmotic pressure in the body, physiological adjustments to salinity fluctuations require the fish to regulate body fluid homeostasis in relation to environmental change via osmoregulation. Previous studies related to osmoregulation were focused primarily on the gill; however, little is known about another organ involved in osmoregulation, the kidney. The salinity adaptation of marine fish involves complex physiological traits, metabolic pathways and molecular and gene networks in osmoregulatory organs. To further explore of the salinity adaptation of marine fish with regard to the role of the kidney, the euryhaline fish Scatophagus argus was employed in the present study. Renal expression profiles of S. argus at different salinity levels were characterized using RNA-sequencing, and an integrated approach of combining molecular tools with physiological and biochemical techniques was utilized to reveal renal osmoregulatory mechanisms in vivo and in vitro. RESULTS: S. argus renal transcriptomes from the hyposaline stress (0‰, freshwater [FW]), hypersaline stress (50‰, hypersaline water [HW]) and control groups (25‰) were compared to elucidate potential osmoregulatory mechanisms. In total, 19,012 and 36,253 differentially expressed genes (DEGs) were obtained from the FW and HW groups, respectively. Based on the functional classification of DEGs, the renal dopamine system-induced Na+ transport was demonstrated to play a fundamental role in osmoregulation. In addition, for the first time in fish, many candidate genes associated with the dopamine system were identified. Furthermore, changes in environmental salinity affected renal dopamine release/reuptake by regulating the expression of genes related to dopamine reuptake (dat and nkaα1), vesicular traffic-mediated dopamine release (pink1, lrrk2, ace and apn), DAT phosphorylation (CaMKIIα and pkcß) and internalization (akt1). The associated transcriptional regulation ensured appropriate extracellular dopamine abundance in the S. argus kidney, and fluctuations in extracellular dopamine produced a direct influence on Na+/K+-ATPase (NKA) expression and activity, which is associated with Na+ homeostasis. CONCLUSIONS: These transcriptomic data provided insight into the molecular basis of renal osmoregulation in S. argus. Significantly, the results of this study revealed the mechanism of renal dopamine system-induced Na+ transport is essential in fish osmoregulation.


Assuntos
Dopamina/metabolismo , Peixes/genética , Rim/metabolismo , Estresse Salino/genética , Sódio/metabolismo , Transcriptoma , Animais , Células Cultivadas , Peixes/metabolismo , Perfilação da Expressão Gênica , Homeostase , Transporte de Íons , Rim/enzimologia , Anotação de Sequência Molecular , Osmorregulação/genética , Potássio/metabolismo , Tolerância ao Sal , Análise de Sequência de RNA , ATPase Trocadora de Sódio-Potássio/metabolismo
16.
Cell Mol Biol (Noisy-le-grand) ; 65(3): 76-83, 2019 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-30942158

RESUMO

The aim of this study is an investigation the protective effects of vitamin C (Vit C), vitamin E (Vit E), ß-carotene, sodium selenate combination in indomethacin-induced gastric mucosal damage in rats. Rats were divided into 6 groups. Group I: Intact animals (control). Group II: Control animals receiving Vit C (100 mg/kg/day), Vit E (100 mg/kg/day), ß-carotene (15 mg/kg/day) and sodium selenate (0.2 mg/kg/day) for 3 days. Group III: Animals receiving 25 mg/kg indomethacin. Group IV: Animals receiving Vit C, Vit E, ß-carotene and sodium selenate (in same doses) for 3 days 2 h before the administration of indomethacin. Group V: Animals receiving ranitidine (150 mg/kg) for 3 days. Group VI: Animals receiving ranitidine for 3 days 2 h before to the administration of indomethacin (in same dose and time). The administration of indomethacin caused a decrease in the levels of glutathione, mucus, hexosamine and in the activities of glutathione-S-transferase, sodium-potassium ATPase, thromboplastic activity and an increase in the aspartate and alanine amino transferase, alkaline phosphatase, catalase, lactate dehydrogenase, myeloperoxidase activities and sialic acid, lipid peroxidation and protein carbonyl levels.  Stomach caspase-8 immun+ cell numbers showed a slight increase while caspase-9 immun+ cell numbers reduced in indomethacin given group compared to control animals. Our results findings suggest that the combination of Vit C, Vit E, ß-carotene, sodium selenate and ranitidine has a protective effect on indomethacin-induced gastric mucosal injury of rats.


Assuntos
Antioxidantes/farmacologia , Mucosa Gástrica/lesões , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Animais , Aspartato Aminotransferases/sangue , Caspases/metabolismo , Catalase/metabolismo , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/enzimologia , Mucosa Gástrica/patologia , Glutationa/sangue , Glutationa Transferase/metabolismo , Hexosaminas/metabolismo , Indometacina , L-Lactato Desidrogenase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Mucinas/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Peroxidase , Ratos Sprague-Dawley , ATPase Trocadora de Sódio-Potássio/metabolismo
17.
Aquat Toxicol ; 211: 92-104, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30954848

RESUMO

The impact of freshwater (FW) salinization on osmoregulation as well as tracheal gill morphology and function was examined in nymphs of the mayfly Hexagenia rigida following exposure to salt contaminated water (SCW, 7.25 g/l NaCl) for a 7-day period. Ionoregulatory homeostasis was perturbed in SCW exposed H. rigida nymphs as indicated by increased hemolymph Na+, K+ and Cl- levels as well as hemolymph pH and water content. Despite this, SCW did not alter gill Na+-K+-ATPase (NKA) or V-type H+-ATPase (VA) activity. In addition, NKA and VA immunolocalization in gill ionocytes did not show alterations in enzyme location or changes in ionocyte abundance. The latter observation was confirmed using scanning electron microscopy (SEM) to examine exposed tracheal gill ionocyte numbers. Ionocyte surface morphometrics also revealed that SCW did not change individual ionocyte surface area or ionocyte fractional surface area. Nevertheless, analysis of Na+ movement across the tracheal gill of mayfly nymphs using scanning ion-selective electrode technique indicated that FW nymphs acquired Na+ from surrounding water, while tracheal gills of SCW nymphs had the capacity to secrete Na+. Because Na+ secretion across the gill of SCW-exposed animals occurred in the absence of any change in (1) NKA and VA activity or (2) ionocyte numbers/surface exposure, it was reasoned that Na+ movement across the gill of SCW animals may be occurring, at least in part, through the paracellular pathway. The ultrastructure of tracheal gill septate junctions (SJs) supported this idea as they exhibited morphological alterations indicative of a leakier pathway. Data provide a first look at alterations in osmoregulatory mechanisms that allow H. rigida nymphs to tolerate sub-lethal salinization of their surroundings.


Assuntos
Ephemeroptera/efeitos dos fármacos , Água Doce/química , Brânquias/efeitos dos fármacos , Osmorregulação/efeitos dos fármacos , Cloreto de Sódio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ephemeroptera/metabolismo , Brânquias/metabolismo , Hemolinfa/metabolismo , Salinidade , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Equilíbrio Hidroeletrolítico/efeitos dos fármacos
18.
Aquat Toxicol ; 211: 193-201, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31005768

RESUMO

Lead is one of the most alarming toxic pollutants for the environment due to its acute toxicity and high bioaccumulation tendency. Despite legislative efforts, world lead production has more than doubled since the early 1970s to 2016. Due to extensive exploitation and human activity, the coastal and estuarine regions belong to marine environments that are mostly and more rapidly deteriorated by pollutants including lead. A limited number of studies examined the effects of lead in fishes, compared to other aquatic models and even fewer studies have been dedicated to seawater fishes especially regarding Pb adsorption and accumulation in specific organs. Fish gills, key compartments involved in several crucial functions such as gas exchange, osmoregulation, and excretion, are also the organs in which Pb is mainly accumulated. Herein, we investigated the morphofunctional and ultrastructural modifications in the gills of a marine teleost (Thalassoma pavo) after acute exposure (48, 96, 192 h) to three lead concentrations. We showed that pathological alterations can be detected in all the examined samples. The most common modifications observed were: the curling of the lamellae and the dilation of their apical tips, the lamellar edema, the proliferation and the hypertrophy of CCs, the progressive epithelial disorganization with detachment of the epithelium from connective tissue. This study also demonstrates that there is a weak influence on the expression pattern of Na+/K+-ATPase and AQP3 biomarker enzymes while high metallothioneins expression has been observed. The described alterations may adversely affect gas exchange and ionic balance, with a long chain of cascading effects. This is the first evidence of the effects exerted by lead on gills of seawater fishes that highlights the harmful properties of this metal, even at low concentration.


Assuntos
Brânquias , Chumbo/toxicidade , Perciformes/metabolismo , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Animais , Brânquias/efeitos dos fármacos , Brânquias/ultraestrutura , Metalotioneína/metabolismo , Osmorregulação/efeitos dos fármacos , ATPase Trocadora de Sódio-Potássio/metabolismo , Equilíbrio Hidroeletrolítico/efeitos dos fármacos
19.
Artigo em Inglês | MEDLINE | ID: mdl-31010095

RESUMO

In this study, several lines of evidence are provided to show that Na + , K + -ATPase activity exerts vital roles in normal brain development and function and that loss of enzyme activity is implicated in neurodevelopmental, neuropsychiatric and neurodegenerative disorders, as well as increased risk of cancer, metabolic, pulmonary and cardiovascular disease. Evidence is presented to show that fluoride (F) inhibits Na + , K + -ATPase activity by altering biological pathways through modifying the expression of genes and the activity of glycolytic enzymes, metalloenzymes, hormones, proteins, neuropeptides and cytokines, as well as biological interface interactions that rely on the bioavailability of chemical elements magnesium and manganese to modulate ATP and Na + , K + -ATPase enzyme activity. Taken together, the findings of this study provide unprecedented insights into the molecular mechanisms and biological pathways by which F inhibits Na + , K + -ATPase activity and contributes to the etiology and pathophysiology of diseases associated with impairment of this essential enzyme. Moreover, the findings of this study further suggest that there are windows of susceptibility over the life course where chronic F exposure in pregnancy and early infancy may impair Na + , K + -ATPase activity with both short- and long-term implications for disease and inequalities in health. These findings would warrant considerable attention and potential intervention, not to mention additional research on the potential effects of F intake in contributing to chronic disease.


Assuntos
Fluoretos/farmacologia , Saúde Pública , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Encéfalo/enzimologia , Encéfalo/crescimento & desenvolvimento , Exposição Ambiental , Fluoretos/metabolismo , Humanos , Minerais/metabolismo
20.
Environ Toxicol ; 34(7): 781-787, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30884105

RESUMO

To evaluate the impact of DCAcAm on zebrafish gill, we measure the responses of antioxidant enzyme (superoxide dismutase, SOD), lipid peroxidation (malondialdehyde, MDA), ATPase (Na+ /K+ -ATPase and Ca2+ /Mg2+ -ATP) and histopathological changes of gill in adult zebrafish, after exposed to different concentrations of DCAcAm (0, 1, 10, 100, and 1000 µg L-1 ) for 30 days. Results indicated that DCAcAm first increased and then decreased SOD activity, and DCAcAm also lowered the activities of Na+ /K+ -ATPase and Ca2+ /Mg2+ -ATPase. These results indicated that high affinity of DCAcAm probably be a main factor, which can damage the structures of enzymes, thereby inhibiting the SOD and ATPase activities. Besides, histopathological investigation results also manifested that chronic exposure to DCAcAm can damage the gill tissues, disrupting the normal function of gills. We conclude that chronic exposure to DCAcAm was harmful to organisms, not only influence gill function, but also further cause damage on the gill tissues.


Assuntos
Acetamidas/toxicidade , Brânquias/efeitos dos fármacos , Brânquias/patologia , Poluentes Químicos da Água/toxicidade , Peixe-Zebra , Animais , Antioxidantes/metabolismo , Exposição Ambiental , Brânquias/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Tempo , Peixe-Zebra/anatomia & histologia , Peixe-Zebra/metabolismo
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