scholarly journals βA3/A1-crystallin regulates apical polarity and EGFR endocytosis in retinal pigmented epithelial cells

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Peng Shang ◽  
Nadezda Stepicheva ◽  
Kenneth Teel ◽  
Austin McCauley ◽  
Christopher Scott Fitting ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Structural Element ◽  
Membrane Turnover ◽  
Transfer Protein ◽  
Apical Side ◽  
Egfr Activation ◽  
Signaling Axis ◽  
Epidermal Growth ◽  
Phosphatidylinositol Transfer ◽  
Network Disruption

AbstractThe retinal pigmented epithelium (RPE) is a monolayer of multifunctional cells located at the back of the eye. High membrane turnover and polarization, including formation of actin-based apical microvilli, are essential for RPE function and retinal health. Herein, we demonstrate an important role for βA3/A1-crystallin in RPE. βA3/A1-crystallin deficiency leads to clathrin-mediated epidermal growth factor receptor (EGFR) endocytosis abnormalities and actin network disruption at the apical side that result in RPE polarity disruption and degeneration. We found that βA3/A1-crystallin binds to phosphatidylinositol transfer protein (PITPβ) and that βA3/A1-crystallin deficiency diminishes phosphatidylinositol 4,5-biphosphate (PI(4,5)P2), thus probably decreasing ezrin phosphorylation, EGFR activation, internalization, and degradation. We propose that βA3/A1-crystallin acquired its RPE function before evolving as a structural element in the lens, and that in the RPE, it modulates the PI(4,5)P2 pool through PITPβ/PLC signaling axis, coordinates EGFR activation, regulates ezrin phosphorylation and ultimately the cell polarity.

Neutrophil elastase induces mucin production by ligand-dependent epidermal growth factor receptor activation

2002 ◽  
Vol 283 (3) ◽  
pp. L531-L540 ◽  
Author(s):  
Kazuhiro Kohri ◽  
Iris F. Ueki ◽  
Jay A. Nadel
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Neutrophil Elastase ◽  
Growth Factor Receptor ◽  
Receptor Activation ◽  
Cell Culture Supernatant ◽  
Mucin Production ◽  
Egfr Activation ◽  
Epidermal Growth

Neutrophil products are implicated in hypersecretory airway diseases. To determine the mechanisms linking a proteolytic effect of human neutrophil elastase (HNE) and mucin overproduction, we examined the effects of HNE on MUC5AC mucin production in human airway epithelial (NCI-H292) cells. Stimulation with HNE for 5–30 min induced MUC5AC production 24 h later, which was prevented by HNE serine active site inhibitors, implicating a proteolytic effect of HNE. MUC5AC induction was preceded by epidermal growth factor receptor (EGFR) tyrosine phosphorylation and was prevented by selective EGFR tyrosine kinase inhibitors, implicating EGFR activation. HNE-induced MUC5AC production was inhibited by a neutralizing transforming growth factor-α (TGF-α, an EGFR ligand) antibody and by a neutralizing EGFR antibody but not by oxygen free radical scavengers, further implicating TGF-α and ligand-dependent EGFR activation in the response. HNE decreased pro-TGF-α in NCI-H292 cells and increased TGF-α in cell culture supernatant. From these results, we conclude that HNE-induced MUC5AC mucin production occurs via its proteolytic activation of an EGFR signaling cascade involving TGF-α.

scholarly journals Integrin α1β1 Regulates Epidermal Growth Factor Receptor Activation by Controlling Peroxisome Proliferator-Activated Receptor γ-Dependent Caveolin-1 Expression

2010 ◽  
Vol 30 (12) ◽  
pp. 3048-3058 ◽  
Author(s):  
Xiwu Chen ◽  
Carrie Whiting ◽  
Corina Borza ◽  
Wen Hu ◽  
Stacey Mont ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Peroxisome Proliferator ◽  
Ros Production ◽  
Peroxisome Proliferator Activated Receptor ◽  
Caveolin 1 ◽  
Egfr Activation ◽  
Epidermal Growth

ABSTRACT Integrin α1β1 negatively regulates the generation of profibrotic reactive oxygen species (ROS) by inhibiting epidermal growth factor receptor (EGFR) activation; however, the mechanism by which it does this is unknown. In this study, we show that caveolin-1 (Cav-1), a scaffolding protein that binds integrins and controls growth factor receptor signaling, participates in integrin α1β1-mediated EGFR activation. Integrin α1-null mesangial cells (MCs) have reduced Cav-1 levels, and reexpression of the integrin α1 subunit increases Cav-1 levels, decreases EGFR activation, and reduces ROS production. Downregulation of Cav-1 in wild-type MCs increases EGFR phosphorylation and ROS synthesis, while overexpression of Cav-1 in the integrin α1-null MCs decreases EGFR-mediated ROS production. We further show that integrin α1-null MCs have increased levels of activated extracellular signal-regulated kinase (ERK), which leads to reduced activation of peroxisome proliferator-activated receptor γ (PPARγ), a transcription factor that positively regulates Cav-1 expression. Moreover, activation of PPARγ or inhibition of ERK increases Cav-1 levels in the integrin α1-null MCs. Finally, we show that glomeruli of integrin α1-null mice have reduced levels of Cav-1 and activated PPARγ but increased levels of phosphorylated EGFR both at baseline and following injury. Thus, integrin α1β1 negatively regulates EGFR activation by positively controlling Cav-1 levels, and the ERK/PPARγ axis plays a key role in regulating integrin α1β1-dependent Cav-1 expression and consequent EGFR-mediated ROS production.

A Conjugate of an Anti-Epidermal Growth Factor Receptor (EGFR) VHH and a Cell-Penetrating Peptide Drives Receptor Internalization and Blocks EGFR Activation

ChemBioChem ◽  
2017 ◽  
Vol 18 (24) ◽  
pp. 2390-2394 ◽  
Author(s):  
Sanne A. M. van Lith ◽  
Dirk van den Brand ◽  
Rike Wallbrecher ◽  
Sander M. J. van Duijnhoven ◽  
Roland Brock ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Receptor Internalization ◽  
Cell Penetrating Peptide ◽  
Egfr Activation ◽  
Cell Penetrating ◽  
A Cell ◽  
Epidermal Growth

Epidermal growth factor receptor is involved in enterocyte anoikis through the dismantling of E-cadherin-mediated junctions

2009 ◽  
Vol 296 (2) ◽  
pp. G235-G244 ◽  
Author(s):  
Verónica-Haydée Lugo-Martínez ◽  
Constance S. Petit ◽  
Stéphane Fouquet ◽  
Johanne Le Beyec ◽  
Jean Chambaz ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Basal Lamina ◽  
Intestinal Epithelium ◽  
Adherens Junctions ◽  
Growth Factor Receptor ◽  
Egfr Activation ◽  
Epidermal Growth ◽  
E Cadherin

Enterocytes of the intestinal epithelium are continually regenerated. They arise from precursor cells in crypts, migrate along villi, and finally die, 3–4 days later, when they reach the villus apex. Their death is thought to occur by anoikis, a form of apoptosis induced by cell detachment, but the mechanism of this process remains poorly understood. We have previously shown that a key event in the onset of anoikis in normal enterocytes detached from the basal lamina is the disruption of adherens junctions mediated by E-cadherin (Fouquet S, Lugo-Martinez VH, Faussat AM, Renaud F, Cardot P, Chambaz J, Pincon-Raymond M, Thenet S. J Biol Chem 279: 43061–43069, 2004). Here we have further investigated the mechanisms underlying this disassembly of the adherens junctions. We show that disruption of the junctions occurs through endocytosis of E-cadherin and that this process depends on the tyrosine-kinase activity of the epidermal growth factor receptor (EGFR). Activation of EGFR was detected in detached enterocytes before E-cadherin disappearance. Specific inhibition of EGFR by tyrphostin AG-1478 maintained E-cadherin and its cytoplasmic partners β- and α-catenin at cell-cell contacts and decreased anoikis. Finally, EGFR activation was evidenced in the intestinal epithelium in vivo, in rare individual cells, which were shown to lose their interactions with the basal lamina. We conclude that EGFR is activated as enterocytes become detached from the basal lamina, and that this mechanism contributes to the disruption of E-cadherin-dependent junctions leading to anoikis. This suggests that EGFR participates in the physiological elimination of the enterocytes.

scholarly journals Epithelial EGF receptor signaling mediates airway hyperreactivity and remodeling in a mouse model of chronic asthma

2011 ◽  
Vol 300 (3) ◽  
pp. L414-L421 ◽  
Author(s):  
Timothy D. Le Cras ◽  
Thomas H. Acciani ◽  
Elizabeth M. Mushaben ◽  
Elizabeth L. Kramer ◽  
Patricia A. Pastura ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Growth Factor Receptor ◽  
Airway Hyperreactivity ◽  
Egfr Signaling ◽  
Egfr Activation ◽  
Epidermal Growth

Increases in the epidermal growth factor receptor (EGFR) have been associated with the severity of airway thickening in chronic asthmatic subjects, and EGFR signaling is induced by asthma-related cytokines and inflammation. The goal of this study was to determine the role of EGFR signaling in a chronic allergic model of asthma and specifically in epithelial cells, which are increasingly recognized as playing an important role in asthma. EGFR activation was assessed in mice treated with intranasal house dust mite (HDM) for 3 wk. EGFR signaling was inhibited in mice treated with HDM for 6 wk, by using either the drug erlotinib or a genetic approach that utilizes transgenic mice expressing a mutant dominant negative epidermal growth factor receptor in the lung epithelium (EGFR-M mice). Airway hyperreactivity (AHR) was assessed by use of a flexiVent system after increasing doses of nebulized methacholine. Airway smooth muscle (ASM) thickening was measured by morphometric analysis. Sensitization to HDM (IgG and IgE), inflammatory cells, and goblet cell changes were also assessed. Increased EGFR activation was detected in HDM-treated mice, including in bronchiolar epithelial cells. In mice exposed to HDM for 6 wk, AHR and ASM thickening were reduced after erlotinib treatment and in EGFR-M mice. Sensitization to HDM and inflammatory cell counts were similar in all groups, except neutrophil counts, which were lower in the EGFR-M mice. Goblet cell metaplasia with HDM treatment was reduced by erlotinib, but not in EGFR-M transgenic mice. This study demonstrates that EGFR signaling, especially in the airway epithelium, plays an important role in mediating AHR and remodeling in a chronic allergic asthma model.

scholarly journals Regulation of Epidermal Growth Factor Receptor Signaling by Endocytosis and Intracellular Trafficking

2001 ◽  
Vol 12 (6) ◽  
pp. 1897-1910 ◽  
Author(s):  
Patrick Burke ◽  
Kevin Schooler ◽  
H. Steven Wiley
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Egfr Signaling ◽  
Egfr Activation ◽  
Early Endosomes ◽  
Epidermal Growth ◽  
Growth Factor Receptor Signaling ◽  
Regulated Trafficking

Ligand activation of the epidermal growth factor receptor (EGFR) leads to its rapid internalization and eventual delivery to lysosomes. This process is thought to be a mechanism to attenuate signaling, but signals could potentially be generated after endocytosis. To directly evaluate EGFR signaling during receptor trafficking, we developed a technique to rapidly and selectively isolate internalized EGFR and associated molecules with the use of reversibly biotinylated anti-EGFR antibodies. In addition, we developed antibodies specific to tyrosine-phosphorylated EGFR. With the use of a combination of fluorescence imaging and affinity precipitation approaches, we evaluated the state of EGFR activation and substrate association during trafficking in epithelial cells. We found that after internalization, EGFR remained active in the early endosomes. However, receptors were inactivated before degradation, apparently due to ligand removal from endosomes. Adapter molecules, such as Shc, were associated with EGFR both at the cell surface and within endosomes. Some molecules, such as Grb2, were primarily found associated with surface EGFR, whereas others, such as Eps8, were found only with intracellular receptors. During the inactivation phase, c-Cbl became EGFR associated, consistent with its postulated role in receptor attenuation. We conclude that the association of the EGFR with different proteins is compartment specific. In addition, ligand loss is the proximal cause of EGFR inactivation. Thus, regulated trafficking could potentially influence the pattern as well as the duration of signal transduction.

scholarly journals Involvement of Oxidative Stress and the Epidermal Growth Factor Receptor in Diesel Exhaust Particle-Induced Expression of Inflammatory Mediators in Human Mononuclear Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Fangfang Li ◽  
Zhen An ◽  
Haibin Li ◽  
Xia Gao ◽  
Gui Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Diesel Exhaust ◽  
Mononuclear Cells ◽  
Growth Factor Receptor ◽  
Proinflammatory Mediators ◽  
Human Mononuclear Cells ◽  
Egfr Activation ◽  
Epidermal Growth

Exposure to diesel exhaust particles (DEPs) has been associated with increased incidence of cardiopulmonary diseases. This study is aimed at examining the proinflammatory effects of DEP on primary human peripheral blood mononuclear cells (PBMC) and the underlying mechanisms using a human mononuclear cell line, THP-1. DEPs were incubated with the PBMC and THP-1 cells for 24 h, respectively. The supernatants were collected and subjected to measurement of proinflammatory mediators including interleukin 8 (IL-8) or tumor necrosis factor α (TNFα) by ELISA. Levels of reactive oxygen species (ROS) were determined using flow cytometry. Phosphorylation of the epidermal growth factor receptor (EGFR) was examined with immunoblotting. Exposure to DEP induced a concentration-dependent increase in the expression of IL-8 and TNFα in the PBMC and THP-1 cells. Further mechanistic studies with THP-1 cells indicated that DEP stimulation increased intracellular levels of ROS, an indicator of oxidative stress, and phosphorylation of the EGFR, indicative of EGFR activation. Pretreatment of THP-1 cells with the antioxidant N-acetyl-L-cysteine (NAC) markedly blunted DEP-induced EGFR phosphorylation, indicating that oxidative stress was involved in DEP-induced EGFR activation. Furthermore, the pretreatment of THP-1 cells with either NAC or a selective EGFR inhibitor significantly blocked DEP-induced IL-8 expression, implying that oxidative stress and subsequent EGFR activation mediated DEP-induced inflammatory response. In summary, DEP stimulation increases the expression of proinflammatory mediators in human mononuclear cells, which is regulated by oxidative stress-EGFR signaling pathway.

Sign in / Sign up

Export Citation Format

Share Document