scholarly journals Vascular Endothelial Growth Factor Inhibits Phagocytosis of Apoptotic Cells by Airway Epithelial Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Mimi Mu ◽  
Peiyu Gao ◽  
Jing He ◽  
Xiangnan Tao ◽  
Chuanwang Song
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Epithelial Cells ◽  
Airway Inflammation ◽  
Allergic Airway Inflammation ◽  
Airway Epithelial Cells ◽  
Apoptotic Cells ◽  
Vascular Endothelial ◽  
Airway Epithelial ◽  
Vegf Inhibition ◽  
Endothelial Growth Factor

Professional phagocytes such as dendritic cells and macrophages can ingest particles larger than 0.5 μm in diameter. Epithelial cells are nonprofessional phagocytes that cannot ingest pathogenic microorganisms, but they can ingest apoptotic cells. Inhibition of the engulfment of apoptotic cells by the airway epithelium can cause severe airway inflammation. Vascular endothelial growth factor (VEGF) is an angiogenesis-promoting factor that can mediate allergic airway inflammation and can promote airway epithelial cells (AECs) proliferation, but it is not clear whether it affects the engulfment of apoptotic cells by AECs. In the present study, VEGF inhibited engulfment of apoptotic cells by AECs via binding to VEGF receptor(R)2. This inhibitory effect of VEGF was not influenced by masking of phosphatidylserine (PS) on the surface of apoptotic cells and was partially mediated by the PI3K-Akt signaling pathway. VEGF inhibition of phagocytosis involved polymerization of actin and downregulation of the expression of the phagocytic-associated protein Beclin-1 in AECs. Since engulfment of apoptotic cells by AECs is an important mechanism for airway inflammation regression, VEGF inhibition of the engulfment of apoptotic cells by airway epithelial cells may be important for mediating allergic airway inflammation.

scholarly journals Intelectin is required for IL-13-induced monocyte chemotactic protein-1 and -3 expression in lung epithelial cells and promotes allergic airway inflammation

2010 ◽  
Vol 298 (3) ◽  
pp. L290-L296 ◽  
Author(s):  
Naibing Gu ◽  
Guannan Kang ◽  
Chang'E Jin ◽  
Yongjian Xu ◽  
Zhenxiang Zhang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Airway Inflammation ◽  
Airway Epithelium ◽  
Allergic Airway Inflammation ◽  
Airway Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Mouse Lung ◽  
Airway Epithelial ◽  
Chemotactic Protein ◽  
Lung Epithelial

Asthma is characterized by airway inflammation, mucus overproduction, airway hyperreactivity, and peribronchial fibrosis. Intelectin has been shown to be increased in airway epithelium of asthmatics. However, the role of intelectin in the pathogenesis of asthma is unknown. Airway epithelial cells can secrete chemokines such as monocyte chemotactic protein (MCP)-1 and -3 that play crucial roles in asthmatic airway inflammation. We hypothesized that intelectin plays a role in allergic airway inflammation by regulating chemokine expression. In a mouse allergic asthma model, we found that mRNA expression of intelectin-2 as well as MCP-1 and -3 in mouse lung was increased very early (within 2 h) after allergen challenge. Expression of intelectin protein was localized to mucous cells in airway epithelium. Treatment of MLE12 mouse lung epithelial cells with interleukin IL-13, a critical mediator of allergic airway disease, induced expression of intelectin-1 and -2 as well as MCP-1 and -3. When IL-13-induced intelectin-1 and -2 expression was inhibited by RNA interference, IL-13-induced extracellular signal-regulated kinase 1/2 phosphorylation and MCP-1 and -3 production by MLE12 cells was inhibited. Furthermore, inhibition of intelectin expression by airway transfection with shRNA targeting intelectin-1 and -2 attenuated allergen-induced airway inflammation. We conclude that intelectin, a molecule expressed by airway epithelial cells and upregulated in asthma, is required for IL-13-induced MCP-1 and -3 production in mouse lung epithelial cells and contributes to allergic airway inflammation.

MTOR suppresses autophagy-mediated production of IL25 in allergic airway inflammation

Thorax ◽  
2020 ◽  
Vol 75 (12) ◽  
pp. 1047-1057
Author(s):  
Wen Li ◽  
Yinfang Wu ◽  
Yun Zhao ◽  
Zhouyang Li ◽  
Haixia Chen ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Airway Inflammation ◽  
Airway Epithelium ◽  
Allergen Challenge ◽  
Allergic Airway Inflammation ◽  
Bronchial Epithelium ◽  
Airway Epithelial Cells ◽  
House Dust Mites ◽  
Airway Epithelial ◽  
Asthmatic Patients

IntroductionAirway epithelial cells are recognised as an essential controller for the initiation and perpetuation of asthmatic inflammation, yet the detailed mechanisms remain largely unknown. This study aims to investigate the roles and mechanisms of the mechanistic target of rapamycin (MTOR)–autophagy axis in airway epithelial injury in asthma.MethodsWe examined the MTOR–autophagy signalling in airway epithelium from asthmatic patients or allergic mice induced by ovalbumin or house dust mites, or in human bronchial epithelial (HBE) cells. Furthermore, mice with specific MTOR knockdown in airway epithelium and autophagy-related lc3b-/- mice were used for allergic models.ResultsMTOR activity was decreased, while autophagy was elevated, in airway epithelium from asthmatic patients or allergic mice, or in HBE cells treated with IL33 or IL13. These changes were associated with upstream tuberous sclerosis protein 2 signalling. Specific MTOR knockdown in mouse bronchial epithelium augmented, while LC3B deletion diminished allergen-induced airway inflammation and mucus hyperproduction. The worsened inflammation caused by MTOR deficiency was also ameliorated in lc3b-/- mice. Mechanistically, autophagy was induced later than the emergence of allergen-initiated inflammation, particularly IL33 expression. MTOR deficiency increased, while knocking out of LC3B abolished the production of IL25 and the eventual airway inflammation on allergen challenge. Blocking IL25 markedly attenuated the exacerbated airway inflammation in MTOR-deficiency mice.ConclusionCollectively, these results demonstrate that allergen-initiated inflammation suppresses MTOR and induces autophagy in airway epithelial cells, which results in the production of certain proallergic cytokines such as IL25, further promoting the type 2 response and eventually perpetuating airway inflammation in asthma.

scholarly journals The type 2 vascular endothelial growth factor receptor recruits insulin receptor substrate-1 in its signalling pathway

2002 ◽  
Vol 368 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Duraisamy SENTHIL ◽  
Goutam GHOSH CHOUDHURY ◽  
Basant K. BHANDARI ◽  
Balakuntalam S. KASINATH
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Protein Synthesis ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Tyrosine Phosphorylation ◽  
Kinase Activity ◽  
Insulin Receptor Substrate ◽  
Vascular Endothelial ◽  
Endothelial Growth Factor

Vascular endothelial growth factor (VEGF) isoforms exert their biological effects through receptors that possess intrinsic tyrosine kinase activity. Whether VEGF binding to its receptors recruits insulin receptor substrate (IRS) family of docking proteins to the receptor is not known. Following incubation of mouse kidney proximal tubular epithelial cells with VEGF, we observed an increase in tyrosine phosphorylation of several proteins, including one of 200kDa, suggesting possible regulation of phosphorylation of IRS proteins. VEGF augmented tyrosine phosphorylation of IRS-1 in kidney epithelial cells and rat heart endothelial cells in a time-dependent manner. In the epithelial cells, association of IRS-1 with type 2 VEGF receptor was promoted by VEGF. VEGF also increased association of IRS-1 with the p85 regulatory subunit of phosphoinositide 3-kinase (PI 3-kinase), and PI 3-kinase activity in IRS-1 immunoprecipitates was increased in VEGF-treated cells. Incubation of epithelial cells with antisense IRS-1 oligonucleotide, but not sense oligonucleotide, reduced expression of the protein and VEGF-induced PI 3-kinase activity in IRS-1 immunoprecipitates. Additionally, VEGF-induced protein synthesis was also impaired by antisense but not sense IRS-1 oligonucleotide. These data provide the first evidence that binding of VEGF to its type 2 receptor promotes association of IRS-1 with the receptor complex. This association may account for some of the increase in VEGF-induced PI 3-kinase activity, and the increase in de novo protein synthesis seen in renal epithelial cells.

scholarly journals Regulation of epithelium-specific Ets-like factors ESE-1 and ESE-3 in airway epithelial cells: potential roles in airway inflammation

Cell Research ◽  
2008 ◽  
Vol 18 (6) ◽  
pp. 649-663 ◽  
Author(s):  
Jing Wu ◽  
Rongqi Duan ◽  
Huibi Cao ◽  
Deborah Field ◽  
Catherine M Newnham ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Airway Inflammation ◽  
Airway Epithelial Cells ◽  
Airway Epithelial
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