scholarly journals Endogenous surface expression of ΔF508-CFTR mediates cAMP-stimulated Cl−current in CFTRΔF508/ΔF508pig thyroid epithelial cells

2011 ◽  
Vol 97 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Yonghai Li ◽  
Suhasini Ganta ◽  
Peying Fong
Keyword(s):  
Epithelial Cells ◽  
Surface Expression ◽  
Δf508 Cftr

Calcium-pump inhibitors induce functional surface expression of ΔF508-CFTR protein in cystic fibrosis epithelial cells

2002 ◽  
Vol 8 (5) ◽  
pp. 485-492 ◽  
Author(s):  
Marie E. Egan ◽  
Judith Glöckner-Pagel ◽  
Catherine A. Ambrose ◽  
Paula A. Cahill ◽  
Lamiko Pappoe ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Surface Expression ◽  
Calcium Pump ◽  
Functional Surface ◽  
Δf508 Cftr ◽  
Cftr Protein

scholarly journals Regulation of endogenous ENaC functional expression by CFTR and ΔF508-CFTR in airway epithelial cells

2011 ◽  
Vol 300 (1) ◽  
pp. L88-L101 ◽  
Author(s):  
Ronald C. Rubenstein ◽  
Shannon R. Lockwood ◽  
Ellen Lide ◽  
Rebecca Bauer ◽  
Laurence Suaud ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Functional Expression ◽  
Surface Expression ◽  
Airway Epithelial Cells ◽  
Cell Surface Expression ◽  
Apical Surface ◽  
Airway Epithelial ◽  
Airway Epithelia ◽  
Δf508 Cftr

The functional expression of the epithelial sodium channel (ENaC) appears elevated in cystic fibrosis (CF) airway epithelia, but the mechanism by which this occurs is not clear. We tested the hypothesis that the cystic fibrosis transmembrane conductance regulator (CFTR) alters the trafficking of endogenously expressed human ENaC in the CFBE41o− model of CF bronchial epithelia. Functional expression of ENaC, as defined by amiloride-inhibited short-circuit current ( Isc) in Ussing chambers, was absent under control conditions but present in CFBE41o− parental and ΔF508-CFTR-overexpressing cells after treatment with 1 μM dexamethasone (Dex) for 24 h. The effect of Dex was mimicked by incubation with the glucocorticoid hydrocortisone but not with the mineralocorticoid aldosterone. Application of trypsin to the apical surface to activate uncleaved, “near-silent” ENaC caused an additional increase in amiloride-sensitive Isc in the Dex-treated cells and was without effect in the control cells, suggesting that Dex increased ENaC cell surface expression. In contrast, Dex treatment did not stimulate amiloride-sensitive Isc in CFBE41o− cells that stably express wild-type (wt) CFTR. CFBE41o− wt cells also had reduced expression of α- and γ-ENaC compared with parental and ΔF508-CFTR-overexpressing cells. Furthermore, application of trypsin to the apical surface of Dex-treated CFBE41o− wt cells did not stimulate amiloride-sensitive Isc, suggesting that ENaC remained absent from the surface of these cells even after Dex treatment. We also tested the effect of trafficking-corrected ΔF508-CFTR on ENaC functional expression. Incubation with 1 mM 4-phenylbutyrate synergistically increased Dex-induced ENaC functional expression in ΔF508-CFTR-overexpressing cells. These data support the hypothesis that wt CFTR can regulate the whole cell, functional, and surface expression of endogenous ENaC in airway epithelial cells and that absence of this regulation may foster ENaC hyperactivity in CF airway epithelia.

scholarly journals GP96 drives exacerbation of secondary bacterial pneumonia following influenza A virus infection

2020 ◽  
Author(s):  
Tomoko Sumitomo ◽  
Masanobu Nakata ◽  
Satoshi Nagase ◽  
Yuki Takahara ◽  
Mariko Honda-Ogawa ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Influenza A Virus ◽  
Transcriptional Repression ◽  
Bacterial Pneumonia ◽  
Influenza A ◽  
Surface Expression ◽  
Lung Pathology ◽  
Direct Binding ◽  
Novel Therapeutic Strategies ◽  
Secondary Bacterial Pneumonia

AbstractInfluenza A virus (IAV) infection predisposes the host to secondary bacterial pneumonia, known as a major cause of morbidity and mortality during influenza epidemics. Analysis of interactions between IAV-infected human epithelial cells and Streptococcus pneumoniae revealed that infected cells ectopically exhibited the endoplasmic reticulum chaperon GP96 on the surface. Importantly, efficient pneumococcal adherence to epithelial cells was imparted by interactions with extracellular GP96 and integrin αV, with the surface expression mediated by GP96 chaperone activity. Furthermore, abrogation of adherence was gained by chemical inhibition or genetic knockout of GP96, as well as addition of RGD peptide. Direct binding of extracellular GP96 and pneumococci was shown to be mediated by pneumococcal oligopeptide permease components. Additionally, IAV infection induced activation of calpains and Snail1, which are responsible for degradation and transcriptional repression of junctional proteins in the host, respectively, indicating increased bacterial translocation across the epithelial barrier. Notably, treatment of IAV-infected mice with the GP96 inhibitor enhanced pneumococcal clearance from lung tissues and ameliorated lung pathology. Taken together, the present findings indicate a viral-bacterial synergy in relation to disease progression and suggest a paradigm for developing novel therapeutic strategies tailored to inhibit pneumococcal colonization in an IAV-infected respiratory tract.

scholarly journals Aldosterone Stimulates Activity and Surface Expression of NHE3 in Human Primary Proximal Tubule Epithelial Cells (RPTEC)

2006 ◽  
Vol 17 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
Karina Drumm ◽  
Theresia R. Kress ◽  
Birgit Gassner ◽  
Alexander W. Krug ◽  
Michael Gekle
Keyword(s):  
Epithelial Cells ◽  
Proximal Tubule ◽  
Surface Expression

CFTR channel insertion to the apical surface in rat duodenal villus epithelial cells is upregulated by VIP in vivo

1999 ◽  
Vol 112 (6) ◽  
pp. 887-894
Author(s):  
N.A. Ameen ◽  
B. Martensson ◽  
L. Bourguinon ◽  
C. Marino ◽  
J. Isenberg ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Apical Membrane ◽  
Surface Expression ◽  
Apical Plasma Membrane ◽  
Intracellular Camp ◽  
Apical Surface ◽  
C Terminus ◽  
Confocal Immunofluorescence ◽  
Small Intestinal Villus

cAMP activated insertion of the cystic fibrosis transmembrane conductance regulator (CFTR) channels from endosomes to the apical plasma membrane has been hypothesized to regulate surface expression and CFTR function although the physiologic relevance of this remains unclear. We previously identified a subpopulation of small intestinal villus epithelial cells or CFTR high expressor (CHE) cells possessing very high levels of apical membrane CFTR in association with a prominent subapical vesicular pool of CFTR. We have examined the subcellular redistribution of CFTR in duodenal CHE cells in vivo in response to the cAMP activated secretagogue vasoactive intestinal peptide (VIP). Using anti-CFTR antibodies against the C terminus of rodent CFTR and indirect immunofluorescence, we show by quantitative confocal microscopy that CFTR rapidly redistributes from the cytoplasm to the apical surface upon cAMP stimulation by VIP and returns to the cytoplasm upon removal of VIP stimulation of intracellular cAMP levels. Using ultrastructural and confocal immunofluorescence examination in the presence or absence of cycloheximide, we also show that redistribution was not dependent on new protein synthesis, changes in endocytosis, or rearrangement of the apical cytoskeleton. These observations suggest that physiologic cAMP activated apical membrane insertion and recycling of CFTR channels in normal CFTR expressing epithelia contributes to the in vivo regulation of CFTR mediated anion transport.

Effects of Indomethacin and NS-398 on Acid-Induced E-Cadherin Surface Expression in Rat Gastric Epithelial Cells

2001 ◽  
pp. 229-232
Author(s):  
Yasuhide Takezono ◽  
Takashi Joh ◽  
Makoto Sasaki ◽  
Hiromi Kataoka ◽  
Kyouji Senou ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Surface Expression ◽  
Gastric Epithelial Cells ◽  
E Cadherin

scholarly journals IRE1α kinase–mediated unconventional protein secretion rescues misfolded CFTR and pendrin

2020 ◽  
Vol 6 (8) ◽  
pp. eaax9914
Author(s):  
Hak Park ◽  
Dong Hoon Shin ◽  
Ju-Ri Sim ◽  
Sowon Aum ◽  
Min Goo Lee
Keyword(s):  
Cell Surface ◽  
Protein Secretion ◽  
Protein Misfolding ◽  
Mammalian Cells ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Downstream Effector ◽  
Mouse Colon ◽  
Δf508 Cftr ◽  
Kinase Pathway

The most prevalent pathogenic mutations in the CFTR (ΔF508) and SLC26A4/pendrin (p.H723R), which cause cystic fibrosis and congenital hearing loss, respectively, evoke protein misfolding and subsequent defects in their cell surface trafficking. Here, we report that activation of the IRE1α kinase pathway can rescue the cell surface expression of ΔF508-CFTR and p.H723R-pendrin through a Golgi-independent unconventional protein secretion (UPS) route. In mammalian cells, inhibition of IRE1α kinase, but not inhibition of IRE1α endonuclease and the downstream effector XBP1, inhibited CFTR UPS. Treatment with the IRE1α kinase activator, (E)-2-(2-chlorostyryl)-3,5,6-trimethyl-pyrazine (CSTMP), rescued cell surface expression and functional activity of ΔF508-CFTR and p.H723R-pendrin. Treatment with a nontoxic dose of CSTMP to ΔF508-CFTR mice restored CFTR surface expression and CFTR-mediated anion transport in the mouse colon. These findings suggest that UPS activation via IRE1α kinase is a strategy to treat diseases caused by defective cell surface trafficking of membrane proteins, including ΔF508-CFTR and p.H723R-pendrin.

scholarly journals Antiviral Activity of Type I, II, and III Interferons Counterbalances ACE2 Inducibility and Restricts SARS-CoV-2

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Idoia Busnadiego ◽  
Sonja Fernbach ◽  
Marie O. Pohl ◽  
Umut Karakus ◽  
Michael Huber ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Antiviral Activity ◽  
Cell Surface ◽  
Cell Line ◽  
Surface Expression ◽  
Type I ◽  
Human Bronchial Epithelial Cells ◽  
Bronchial Epithelial ◽  
Cell Line Model ◽  
Entry Receptor

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), is a recently emerged respiratory coronavirus that has infected >23 million people worldwide with >800,000 deaths. Few COVID-19 therapeutics are available, and the basis for severe infections is poorly understood. Here, we investigated properties of type I (β), II (γ), and III (λ1) interferons (IFNs), potent immune cytokines that are normally produced during infection and that upregulate IFN-stimulated gene (ISG) effectors to limit virus replication. IFNs are already in clinical trials to treat COVID-19. However, recent studies highlight the potential for IFNs to enhance expression of host angiotensin-converting enzyme 2 (ACE2), suggesting that IFN therapy or natural coinfections could exacerbate COVID-19 by upregulating this critical virus entry receptor. Using a cell line model, we found that beta interferon (IFN-β) strongly upregulated expression of canonical antiviral ISGs, as well as ACE2 at the mRNA and cell surface protein levels. Strikingly, IFN-λ1 upregulated antiviral ISGs, but ACE2 mRNA was only marginally elevated and did not lead to detectably increased ACE2 protein at the cell surface. IFN-γ induced the weakest ISG response but clearly enhanced surface expression of ACE2. Importantly, all IFN types inhibited SARS-CoV-2 replication in a dose-dependent manner, and IFN-β and IFN-λ1 exhibited potent antiviral activity in primary human bronchial epithelial cells. Our data imply that type-specific mechanisms or kinetics shape IFN-enhanced ACE2 transcript and cell surface levels but that the antiviral action of IFNs against SARS-CoV-2 counterbalances any proviral effects of ACE2 induction. These insights should aid in evaluating the benefits of specific IFNs, particularly IFN-λ, as repurposed therapeutics. IMPORTANCE Repurposing existing, clinically approved, antiviral drugs as COVID-19 therapeutics is a rapid way to help combat the SARS-CoV-2 pandemic. Interferons (IFNs) usually form part of the body’s natural innate immune defenses against viruses, and they have been used with partial success to treat previous new viral threats, such as HIV, hepatitis C virus, and Ebola virus. Nevertheless, IFNs can have undesirable side effects, and recent reports indicate that IFNs upregulate the expression of host ACE2 (a critical entry receptor for SARS-CoV-2), raising the possibility that IFN treatments could exacerbate COVID-19. Here, we studied the antiviral- and ACE2-inducing properties of different IFN types in both a human lung cell line model and primary human bronchial epithelial cells. We observed differences between IFNs with respect to their induction of antiviral genes and abilities to enhance the cell surface expression of ACE2. Nevertheless, all the IFNs limited SARS-CoV-2 replication, suggesting that their antiviral actions can counterbalance increased ACE2.

Sign in / Sign up

Export Citation Format

Share Document