scholarly journals Heat-Killed Fusobacterium nucleatum Triggers Varying Heme-Related Inflammatory and Stress Responses Depending on Primary Human Respiratory Epithelial Cell Type

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3839
Author(s):  
Ryo Koike ◽  
Marni E. Cueno ◽  
Keiko Nodomi ◽  
Muneaki Tamura ◽  
Noriaki Kamio ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Inflammatory Response ◽  
Stress Responses ◽  
Inflammatory Responses ◽  
Fusobacterium Nucleatum ◽  
Alveolar Epithelial Cells ◽  
Cell Type ◽  
Alveolar Cells ◽  
Epithelial Cell Type ◽  
Alveolar Epithelial

Fusobacterium nucleatum (Fn) is generally an opportunistic oral pathogen that adheres to mammalian mucosal sites, triggering a host inflammatory response. In general, Fn is normally found within the human oral cavity; however, it was previously reported that Fn is a risk factor for certain respiratory diseases. Surprisingly, this was never fully elucidated. Here, we investigated the virulence potential of heat-killed Fn on primary human tracheal, bronchial, and alveolar epithelial cells. In this study, we measured the secretion of inflammatory- (IL-8 and IL-6), stress- (total heme and hydrogen peroxide), and cell death-related (caspase-1 and caspase-3) signals. We established that the inflammatory response mechanism varies in each epithelial cell type: (1) along tracheal cells, possible Fn adherence would trigger increased heme secretion and regulated inflammatory response; (2) along bronchial cells, potential Fn adherence would simultaneously initiate an increase in secreted H2O2 and inflammatory response (ascribable to decreased secreted heme amounts); and (3) along alveolar cells, putative Fn adherence would instigate the increased secretion of inflammatory responses attributable to a decrease in secreted heme levels. Moreover, regardless of the epithelial cell-specific inflammatory mechanism, we believe these are putative, not harmful. Taken together, we propose that any potential Fn-driven inflammation along the respiratory tract would be initiated by differing epithelial cell-specific inflammatory mechanisms that are collectively dependent on secreted heme.

scholarly journals Alveolar Epithelial Cell Type II as main target of SARS-CoV-2 virus and COVID-19 development via NF-Kb pathway deregulation.

2020 ◽  
Author(s):  
Maurizio Carcaterra ◽  
Cristina Caruso
Keyword(s):  
Molecular Mechanisms ◽  
Virus Disease ◽  
Clinical Manifestations ◽  
Alveolar Epithelial Cells ◽  
Type Ii ◽  
Cell Type ◽  
Alveolar Cells ◽  
Alveolar Epithelial ◽  
Corona Virus ◽  
Number Of Patients

Abstract Background: The Corona Virus Disease (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) requires a rapid solutionand global collaborative efforts in order to define preventive and treatment strategies.Methods: One of the major challenges of this disease is the high number of patients needing advanced respiratory support due to the Acute Respiratory Distress Syndrome (ARDS) as the lung is the major –although not exclusive-target of the virus. The molecular mechanisms, pathogenic drivers and the target cell type(s) in SARSCoV-2 infection are still poorly understood, but the development of a “hyperactive” immune response is proposed to play a role in the evolution of the disease and it is envisioned as a major cause of morbidity and mortality.Results: Here we propose a theory by which the main targets for SARS-CoV-2 are the Type II Alveolar Epithelial Cells and the clinical manifestations of the syndrome are a direct consequence of their involvement. We hypotize the existence of a vicious cycle by which once alveolar damage starts in AEC II cells, the inflammatory state is supported by macrophage proinflammatory polarization (M1), cytokines release and by the activation of the NF-κB pathway.Conclusions: If this theory is confirmed, future therapeutic efforts can be directed to target Type 2 alveolar cells and the molecular pathogenic drivers associated with their dysfunction with currently available therapeutic strategies.

scholarly journals OC-STAMP Overexpression Drives Lung Alveolar Epithelial Cell Type II Senescence in Silicosis

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Tian Li ◽  
Xin-yu Yang ◽  
Ding-jie Xu ◽  
Zi-yi Gao ◽  
Yi-bing Gao ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Er Stress ◽  
Cellular Senescence ◽  
Alveolar Epithelial Cell ◽  
Type Ii ◽  
Cell Type ◽  
Mesenchymal Transition ◽  
Epithelial Cell Type ◽  
Alveolar Epithelial ◽  
Chronic Lung Diseases

Cellular senescence has been considered an important driver of many chronic lung diseases. However, the specific mechanism of cellular senescence in silicosis is still unknown. In the present study, silicotic rats and osteoclast stimulatory transmembrane protein (Ocstamp) overexpression of MLE-12 cells were used to explore the mechanism of OC-STAMP in cellular senescence in alveolar epithelial cell type II (AEC2). We found an increasing level of OC-STAMP in AEC2 of silicotic rats. Overexpression of Ocstamp in MLE-12 cells promoted epithelial-mesenchymal transition (EMT), endoplasmic reticulum (ER) stress, and cellular senescence. Myosin heavy chain 9 (MYH9) was a potential interacting protein of OC-STAMP. Knockdown of Ocstamp or Myh9 inhibited cellular senescence in MLE-12 cells transfected with pcmv6-Ocstamp. Treatment with 4-phenylbutyrate (4-PBA) to inhibit ER stress also attenuated cellular senescence in vitro or in vivo. In conclusion, OC-STAMP promotes cellular senescence in AEC2 in silicosis.

scholarly journals Inhibition Mir-92a Alleviates Oxidative Stress and Apoptosis of Alveolar Epithelial Cells Induced by Lipopolysaccharide Exposure through TLR2/AP-1 Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jian Cui ◽  
Huanhuan Ding ◽  
Yongyuan Yao ◽  
Wei Liu
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Lung Tissue ◽  
Cell Apoptosis ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial Cells ◽  
Rat Lung ◽  
Alveolar Epithelial

Objective. To probe into the role of miR-92a in alleviating oxidative stress and apoptosis of alveolar epithelial cell (AEC) injury induced by lipopolysaccharide (LPS) exposure through the Toll-like receptor (TLR) 2/activator protein-1 (AP-1) pathway. Methods. Acute lung injury (ALI) rat model and ALI alveolar epithelial cell model were constructed to inhibit the expression of miR-92a/TLR2/AP-1 in rat and alveolar epithelial cells (AECs), to detect the changes of oxidative stress, inflammatory response, and cell apoptosis in rat lung tissues and AECs, and to measure the changes of wet-dry weight (W/D) ratio in rat lung tissues. Results. Both inhibition of miR-92a expression and knockout of TLR2 and AP-1 gene could reduce LPS-induced rat ALI, alleviate pulmonary edema, inhibit oxidative stress and inflammatory response, and reduce apoptosis of lung tissue cells. In addition, the TLR2 and AP-1 levels in the lung tissues of ALI rats were noticed to be suppressed when inhibiting the expression of miR-92a, and the AP-1 level was also decreased after the knockout of TLR2 gene. Further, we verified this relationship in AECs and found that inhibition of miR-92a/TLR2/AP-1 also alleviated LPS-induced AEC injury, reduced cell apoptosis, and inhibited oxidative stress and inflammatory response. What is more, like that in rat lung tissue, the phenomenon also existed in AECs, that is, when the expression of miR-92a was inhibited, the expression of TLR2 and AP-1 was inhibited, and silencing TLR2 can reduce the expression level of AP-1. Conclusion. MiR-92a/TLR2/AP-1 is highly expressed in ALI, and its inhibition can improve oxidative stress and inflammatory response and reduce apoptosis of AECs.

scholarly journals Characteristics of Passive Solute Transport across Primary Rat Alveolar Epithelial Cell Monolayers

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 331
Author(s):  
Yong Ho Kim ◽  
Kwang-Jin Kim ◽  
David Z. D’Argenio ◽  
Edward D. Crandall
Keyword(s):  
Epithelial Cell ◽  
Tight Junctions ◽  
Pore Radius ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial Cells ◽  
Type I ◽  
Cell Monolayers ◽  
Alveolar Epithelial ◽  
Epithelial Cell Monolayers ◽  
Hydrophilic Solutes

Primary rat alveolar epithelial cell monolayers (RAECM) were grown without (type I cell-like phenotype, RAECM-I) or with (type II cell-like phenotype, RAECM-II) keratinocyte growth factor to assess passive transport of 11 hydrophilic solutes. We estimated apparent permeability (Papp) in the absence/presence of calcium chelator EGTA to determine the effects of perturbing tight junctions on “equivalent” pores. Papp across RAECM-I and -II in the absence of EGTA are similar and decrease as solute size increases. We modeled Papp of the hydrophilic solutes across RAECM-I/-II as taking place via heterogeneous populations of equivalent pores comprised of small (0.41/0.32 nm radius) and large (9.88/11.56 nm radius) pores, respectively. Total equivalent pore area is dominated by small equivalent pores (99.92–99.97%). The number of small and large equivalent pores in RAECM-I was 8.55 and 1.29 times greater, respectively, than those in RAECM-II. With EGTA, the large pore radius in RAECM-I/-II increased by 1.58/4.34 times and the small equivalent pore radius increased by 1.84/1.90 times, respectively. These results indicate that passive diffusion of hydrophilic solutes across an alveolar epithelium occurs via small and large equivalent pores, reflecting interactions of transmembrane proteins expressed in intercellular tight junctions of alveolar epithelial cells.

On the Presence of a Ciliated Columnar Epithelial Cell Type within the Bovine Cervical Mucosa

1973 ◽  
Vol 36 (5) ◽  
pp. 936-940 ◽  
Author(s):  
R. J. Wordinger ◽  
J. B. Ramsey ◽  
J. F. Dickey ◽  
J. R. Hill
Keyword(s):  
Epithelial Cell ◽  
Cell Type ◽  
Epithelial Cell Type ◽  
Columnar Epithelial Cell ◽  
Cervical Mucosa

CD40 amplifies Fas-mediated apoptosis: a mechanism contributing to emphysema

2012 ◽  
Vol 303 (2) ◽  
pp. L141-L151 ◽  
Author(s):  
Ayako Shigeta ◽  
Yuji Tada ◽  
Ji-Yang Wang ◽  
Shunsuke Ishizaki ◽  
Junichi Tsuyusaki ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Epithelial Cells ◽  
Pulmonary Emphysema ◽  
Alveolar Epithelial Cells ◽  
Alveolar Cells ◽  
Alveolar Epithelial ◽  
Cd40 Stimulation ◽  
Ifn Γ ◽  
Apoptosis And Inflammation

Excessive apoptosis and prolonged inflammation of alveolar cells are associated with the pathogenesis of pulmonary emphysema. We aimed to determine whether CD40 affects alveolar epithelial cells and endothelial cells, with regard to evoking apoptosis and inflammation. Mice were repeatedly treated with agonistic-anti CD40 antibody (Ab), with or without agonistic-anti Fas Ab, and evaluated for apoptosis and inflammation in lungs. Human pulmonary microvascular endothelial cells and alveolar epithelial cells were treated with agonistic anti-CD40 Ab and/or anti-Fas Ab to see their direct effect on apoptosis and secretion of proinflammatory molecules in vitro. Furthermore, plasma soluble CD40 ligand (sCD40L) level was evaluated in patients with chronic obstructive pulmonary disease (COPD). In mice, inhaling agonistic anti-CD40 Ab induced moderate alveolar enlargement. CD40 stimulation, in combination with anti-Fas Ab, induced significant emphysematous changes and increased alveolar cell apoptosis. CD40 stimulation also enhanced IFN-γ-mediated emphysematous changes, not via apoptosis induction, but via inflammation with lymphocyte accumulation. In vitro, Fas-mediated apoptosis was enhanced by CD40 stimulation and IFN-γ in endothelial cells and by CD40 stimulation in epithelial cells. CD40 stimulation induced secretion of CCR5 ligands in endothelial cells, enhanced with IFN-γ. Plasma sCD40L levels were significantly increased in patients with COPD, inversely correlating to the percentage of forced expiratory volume in 1 s and positively correlating to low attenuation area score by CT scan, regardless of smoking history. Collectively CD40 plays a contributing role in the development of pulmonary emphysema by sensitizing Fas-mediated apoptosis in alveolar cells and increasing the secretion of proinflammatory chemokines.

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