Influenza A Virus Infection Induces Apical Redistribution of Na+, K+-ATPase in Lung Epithelial Cells In Vitro and In Vivo.
Ontology highlight
ABSTRACT:
SUBMITTER: Peteranderl C
PROVIDER: S-EPMC6839927 | biostudies-literature | 2019 Sep
REPOSITORIES: biostudies-literature
Publications
Influenza A Virus Infection Induces Apical Redistribution of Na<sup>+</sup>, K<sup>+</sup>-ATPase in Lung Epithelial Cells <i>In Vitro</i> and <i>In Vivo</i>.
Peteranderl Christin C Kuznetsova Irina I Schulze Jessica J Hardt Martin M Lecuona Emilia E Sznajder Jacob I JI Vadász István I Morty Rory E RE Pleschka Stephan S Wolff Thorsten T Herold Susanne S
American journal of respiratory cell and molecular biology 20190901 3
Similar Datasets
Project description:Pseudorabies virus (PRV), an alpha herpesvirus, induces significant economic losses to the swine industry and infects multiple kinds of animals. Therefore, it is of great importance to explore anti-PRV compounds. In this study, to explore the anti-PRV compounds, a library of natural compounds was screened through a cell-based ELISA assay, and it was discovered that bufalin, a Na+/K+-ATPase inhibitor, had a robust inhibitory effect on PRV replication. A time-of-addition experiment and temperature-shift assay showed that bufalin significantly inhibited the entry stage of PRV. NaCl- or KCl-treatment showed that NaCl could enhance the inhibitory effect of bufalin on PRV replication, whereas there was no significant effect under the treatment of KCl. Meanwhile, it was also found that bufalin possessed antiviral activity against other alpha herpesviruses, including human herpes simplex virus type 1 (HSV-1) and chicken Marek's disease virus (MDV). Finally, it was found that bufalin could decrease the viral load in multiple tissues, and reduce the morbidity and mortality in PRV-challenged BALB/c mice. Overall, our findings demonstrated that bufalin has the potential to be developed as an anti-PRV compound.
| S-EPMC10572507 | biostudies-literature
Project description:Ouabain (OUA) is a cardiac glycoside that binds to Na+,K+-ATPase (NKA), a conserved membrane protein that controls cell transmembrane ionic concentrations and requires ATP hydrolysis. At nM concentrations, OUA activates signaling pathways that are not related to its typical inhibitory effect on the NKA pump. Activation of these signaling pathways protects against some types of injury of the kidneys and central nervous system. There are 4 isoforms of the alpha subunit of NKA, which are differentially distributed across tissues and may have different physiological roles. Glial cells are important regulators of injury and inflammation in the brain and express the α1 and α2 NKA isoforms. This study investigated the role of α2 NKA in OUA modulation of the neuroinflammatory response induced by lipopolysaccharide (LPS) in mouse primary glial cell cultures. LPS treatment increased lactate dehydrogenase release, while OUA did not decrease cell viability and blocked LPS-induced NF-κB activation. Silencing α2 NKA prevented ERK and NF-κB activation by LPS. α2 NKA also regulates TNF-α and IL-1β levels. The data reported here indicate a significant role of α2 NKA in regulating central LPS effects, with implications in the associated neuroinflammatory processes.
| S-EPMC5501845 | biostudies-literature
Project description:The affinity for K+ of silkworm Na+/K+-ATPase, which is composed of α and β subunits, is remarkably lower than that of mammalian Na+/K+-ATPase, with a slightly higher affinity for Na+. Because the α subunit had more than 70% identity to the mammalian α subunit in the amino acid sequence, whereas the β subunit, a glycosylated protein, had less than 30% identity to the mammalian β subunit, it was suggested that the β subunit was involved in the affinities for Na+ and K+ of Na+/K+-ATPase. To confirm this hypothesis, we examined whether replacing the silkworm β subunit with the mammalian β subunit affected the affinities for Na+ and K+ of Na+/K+-ATPase. Cloned silkworm α and cloned rat β1 were co-expressed in BM-N cells, a cultured silkworm ovary-derived cell lacking endogenous Na+/K+-ATPase, to construct a hybrid Na+/K+-ATPase, in which the silkworm β subunit was replaced with the rat β1 subunit. The hybrid Na+/K+-ATPase increased the affinity for K+ by 4.1-fold and for Na+ by 0.65-fold compared to the wild-type one. Deglycosylation of the silkworm β subunit did not affect the K+ affinity. These results support the involvement of the β subunit in the Na+ and K+ affinities of Na+/K+-ATPase.
| S-EPMC9483571 | biostudies-literature
Project description:Glioblastoma (GBM) is the most frequent brain cancer with poor prognosis and few therapies and urgently requires effective treatments. Na+/K+-ATPase is considered as a target for GBM therapy and development of anticancer drugs. Cardiac glycosides bind the Na+/K+-ATPase α subunit to inhibit enzymatic activity and are promising candidates for anticancer drug development including GBM. However, the comparatively higher doses required for effective anticancer actions cause severe cardiotoxicity. Selectively targeting the ATPase Na+/K+ transporting subunit beta 2 (ATP1B2) that is not expressed in the heart might avoid the cardiotoxicity. However, the effect of targeting ATP1B2 in GBM remains unknown. In this study, we found that high ATP1B2 expression is significantly associated with poor prognosis of patients with GBM. ATP1B2 silencing in GBM cells resulted in remarkably cell cycle arrest at the G2/M phase and apoptosis with concomitant increase in intracellular Ca2+ and activation of p38 kinase, similar to Na+/K+-ATPase inhibition by the classic cardiac glycoside digoxin. ATP1B2 is expressed higher in glioblastoma stem-like cells (GSCs) than in GBM cells and its downregulation induces apoptosis of GSCs. Furthermore, inducible ATP1B2 knockdown significantly inhibit tumor growth in vivo. Our data suggest ATP1B2 has potential as a therapeutic target for GBM.
| S-EPMC6610052 | biostudies-literature
Project description:NHE3, the apical isoform of the Na(+)/H(+) exchanger, is central to the absorption of salt and water across the intestinal epithelium. We report that treatment of epithelial cells with toxin B of Clostridium difficile, a diarrheal pathogen, causes a pronounced inhibition of NHE3 activity, with little effect on the basolateral NHE1 isoform. Depression of NHE3 activity is accompanied by the translocation of apical exchangers to a subapical endomembrane compartment. Treatment of cells with toxin B increased the fraction of exchangers that were solubilized by nonionic detergents and induced dephosphorylation and extensive redistribution of ezrin. The Rho-kinase inhibitor, Y-27632, also altered the distribution and activity of NHE3. We suggest that inactivation of Rho-family GTPases by clostridial toxin B alters the interaction between NHE3 and the microvillar cytoskeleton, possibly by impairing the ability of ezrin to bridge the exchangers to filamentous actin. Detachment of NHE3 from the actin skeleton would facilitate its internalization, resulting in net disappearance from the apical surface. The consequent inhibition of transport is likely to contribute to the diarrheal effects of C. difficile.
| S-EPMC2234495 | biostudies-literature
Project description:The Na+,K+-ATPase generates electrochemical gradients of Na+ and K+ across the plasma membrane via a functional cycle that includes various phosphoenzyme intermediates. However, the structure and function of these intermediates and how metal fluorides mimick them require further investigation. Here, we describe a 4.0 Å resolution crystal structure and functional properties of the pig kidney Na+,K+-ATPase stabilized by the inhibitor beryllium fluoride (denoted E2-BeFx). E2-BeFx is expected to mimic properties of the E2P phosphoenzyme, yet with unknown characteristics of ion and ligand binding. The structure resembles the E2P form obtained by phosphorylation from inorganic phosphate (Pi) and stabilized by cardiotonic steroids, including a low-affinity Mg2+ site near ion binding site II. Our anomalous Fourier analysis of the crystals soaked in Rb+ (a K+ congener) followed by a low-resolution rigid-body refinement (6.9-7.5 Å) revealed preocclusion transitions leading to activation of the dephosphorylation reaction. We show that the Mg2+ location indicates a site of initial K+ recognition and acceptance upon binding to the outward-open E2P state after Na+ release. Furthermore, using binding and activity studies, we find that the BeFx-inhibited enzyme is also able to bind ADP/ATP and Na+. These results relate the E2-BeFx complex to a transient K+- and ADP-sensitive E∗P intermediate of the functional cycle of the Na+,K+-ATPase, prior to E2P.
| S-EPMC9485054 | biostudies-literature
Project description:Background Recent studies have highlighted a critical role for a group of natriuretic hormones, cardiotonic steroid (CTS), in mediating renal inflammation and fibrosis associated with volume expanded settings, such as chronic kidney disease. Immune cell adhesion is a critical step in the inflammatory response; however, little is currently understood about the potential regulatory role of CTS signaling in this setting. Herein, we tested the hypothesis that CTS signaling through Na+/K+-ATPase α-1 (NKA α-1) enhances immune cell recruitment and adhesion to renal epithelium that ultimately advance renal inflammation. Methods and Results We demonstrate that knockdown of the α-1 isoform of Na/K-ATPase causes a reduction in CTS-induced macrophage infiltration in renal tissue as well reduces the accumulation of immune cells in the peritoneal cavity in vivo. Next, using functional adhesion assay, we demonstrate that CTS-induced increases in the adhesion of macrophages to renal epithelial cells were significantly diminished after reduction of NKA α-1 in either macrophages or renal epithelial cells as well after inhibition of NKA α-1-Src signaling cascade with a specific peptide inhibitor, pNaKtide in vitro. Finally, CTS-induced expression of adhesion markers in both endothelial and immune cells was significantly inhibited in an NKA α-1-Src signaling dependent manner in vitro. Conclusions These findings suggest that CTS potentiates immune cell migration and adhesion to renal epithelium through an NKA α-1-dependent mechanism; our new findings suggest that pharmacological inhibition of this feed-forward loop may be useful in the treatment of renal inflammation associated with renal disease.
| S-EPMC7033897 | biostudies-literature
Project description:The sodium pump (Na,K-ATPase) in animal cells is vital for actively maintaining ATP hydrolysis-powered Na+ and K+ electrochemical gradients across the cell membrane. These ion gradients drive co- and countertransport and are critical for establishing the membrane potential. It has been an enigma how Na,K-ATPase discriminates between Na+ and K+, despite the pumped ion on each side being at a lower concentration than the other ion. Recent crystal structures of analogs of the intermediate conformations E2·Pi·2K+ and Na+-bound E1∼P·ADP suggest that the dimensions of the respective binding sites in Na,K-ATPase are crucial in determining its selectivity. Here, we found that the selectivity at each membrane face is pH-dependent and that this dependence is unique for each face. Most notable was a strong increase in the specific affinity for K+ at the extracellular face (i.e. E2 conformation) as the pH is lowered from 7.5 to 5. We also observed a smaller increase in affinity for K+ on the cytoplasmic side (E1 conformation), which reduced the selectivity for Na+ Theoretical analysis of the pKa values of ion-coordinating acidic amino acid residues suggested that the face-specific pH dependences and Na+/K+ selectivities may arise from the protonation or ionization of key residues. The increase in K+ selectivity at low pH on the cytoplasmic face, for instance, appeared to be associated with Asp808 protonation. We conclude that changes in the ionization state of coordinating residues in Na,K-ATPase could contribute to altering face-specific ion selectivity.
| S-EPMC5808778 | biostudies-literature
Project description:Homeostasis of intravascular volume, Na(+), Cl(-), and K(+) is interdependent and determined by the coordinated activities of structurally diverse mediators in the distal nephron and the distal colon. The behavior of these flux pathways is regulated by the renin-angiotensin-aldosterone system; however, the mechanisms that allow independent modulation of individual elements have been obscure. Previous work has shown that mutations in WNK4 cause pseudohypoaldosteronism type II (PHAII), a disease featuring hypertension with hyperkalemia, due to altered activity of specific Na-Cl cotransporters, K(+) channels, and paracellular Cl(-) flux mediators of the distal nephron. By coexpression studies in Xenopus oocytes, we now demonstrate that WNK4 also inhibits the epithelial Na(+) channel (ENaC), the major mediator of aldosterone-sensitive Na(+) (re)absorption, via a mechanism that is independent of WNK4's kinase activity. This inhibition requires intact C termini in ENaC beta- and gamma-subunits, which contain PY motifs used to target ENaC for clearance from the plasma membrane. Importantly, PHAII-causing mutations eliminate WNK4's inhibition of ENaC, thereby paralleling other effects of PHAII to increase sodium balance. The relevance of these findings in vivo was studied in mice harboring PHAII-mutant WNK4. The colonic epithelium of these mice demonstrates markedly increased amiloride-sensitive Na(+) flux compared with wild-type littermates. These studies identify ENaC as a previously unrecognized downstream target of WNK4 and demonstrate a functional role for WNK4 in the regulation of colonic Na(+) absorption. These findings support a key role for WNK4 in coordinating the activities of diverse flux pathways to achieve integrated fluid and electrolyte homeostasis.
| S-EPMC1805455 | biostudies-literature
Project description: Not available
| S-EPMC7237650 | biostudies-literature