scholarly journals Activated clotting factor X mediates mitochondrial alterations and inflammatory responses via protease-activated receptor signaling in alveolar epithelial cells

2020 ◽  
Vol 869 ◽  
pp. 172875 ◽  
Author(s):  
Alicja Bukowska ◽  
Lorenz Schild ◽  
Philipp Bornfleth ◽  
Daniela Peter ◽  
Cornelia Wiese-Rischke ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Responses ◽  
Alveolar Epithelial Cells ◽  
Clotting Factor ◽  
Receptor Signaling ◽  
Factor X ◽  
Alveolar Epithelial ◽  
Mitochondrial Alterations

scholarly journals Hypercapnia induces injury to alveolar epithelial cells via a nitric oxide-dependent pathway

2000 ◽  
Vol 279 (5) ◽  
pp. L994-L1002 ◽  
Author(s):  
John D. Lang ◽  
Phillip Chumley ◽  
Jason P. Eiserich ◽  
Alvaro Estevez ◽  
Thad Bamberg ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Epithelial Cells ◽  
Cell Injury ◽  
Inflammatory Responses ◽  
Alveolar Epithelial Cells ◽  
No Production ◽  
Inflammatory Reactions ◽  
Alveolar Epithelial ◽  
And Function ◽  
The Impact

Ventilator strategies allowing for increases in carbon dioxide (CO2) tensions (hypercapnia) are being emphasized to ameliorate the consequences of inflammatory-mediated lung injury. Inflammatory responses lead to the generation of reactive species including superoxide (O2 −), nitric oxide (·NO), and their product peroxynitrite (ONOO−). The reaction of CO2 and ONOO− can yield the nitrosoperoxocarbonate adduct ONOOCO2 −, a more potent nitrating species than ONOO−. Based on these premises, monolayers of fetal rat alveolar epithelial cells were utilized to investigate whether hypercapnia would modify pathways of ·NO production and reactivity that impact pulmonary metabolism and function. Stimulated cells exposed to 15% CO2 (hypercapnia) revealed a significant increase in ·NO production and nitric oxide synthase (NOS) activity. Cell 3-nitrotyrosine content as measured by both HPLC and immunofluorescence staining also increased when exposed to these same conditions. Hypercapnia significantly enhanced cell injury as evidenced by impairment of monolayer barrier function and increased induction of apoptosis. These results were attenuated by the NOS inhibitor N-monomethyl-l-arginine. Our studies reveal that hypercapnia modifies ·NO-dependent pathways to amplify cell injury. These results affirm the underlying role of ·NO in tissue inflammatory reactions and reveal the impact of hypercapnia on inflammatory reactions and its potential detrimental influences.

scholarly journals Recombinant ACE2 Expression Is Required for SARS-CoV-2 To Infect Primary Human Endothelial Cells and Induce Inflammatory and Procoagulative Responses

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Jonas Nascimento Conde ◽  
William R. Schutt ◽  
Elena E. Gorbunova ◽  
Erich R. Mackow
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Responses ◽  
Diffuse Alveolar Damage ◽  
Umbilical Vein ◽  
Alveolar Epithelial Cells ◽  
Small Subset ◽  
Upper Respiratory Tract ◽  
Alveolar Epithelial ◽  
Progressive Respiratory Failure ◽  
Ciliated Epithelial Cells

ABSTRACT SARS-CoV-2 causes COVID-19, an acute respiratory distress syndrome (ARDS) characterized by pulmonary edema, viral pneumonia, multiorgan dysfunction, coagulopathy, and inflammation. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) receptors to infect and damage ciliated epithelial cells in the upper respiratory tract. In alveoli, gas exchange occurs across an epithelial-endothelial barrier that ties respiration to endothelial cell (EC) regulation of edema, coagulation, and inflammation. How SARS-CoV-2 dysregulates vascular functions to cause ARDS in COVID-19 patients remains an enigma focused on dysregulated EC responses. Whether SARS-CoV-2 directly or indirectly affects functions of the endothelium remains to be resolved and is critical to understanding SARS-CoV-2 pathogenesis and therapeutic targets. We demonstrate that primary human ECs lack ACE2 receptors at protein and RNA levels and that SARS-CoV-2 is incapable of directly infecting ECs derived from pulmonary, cardiac, brain, umbilical vein, or kidney tissues. In contrast, pulmonary ECs transduced with recombinant ACE2 receptors are infected by SARS-CoV-2 and result in high viral titers (∼1 × 107/ml), multinucleate syncytia, and EC lysis. SARS-CoV-2 infection of ACE2-expressing ECs elicits procoagulative and inflammatory responses observed in COVID-19 patients. The inability of SARS-CoV-2 to directly infect and lyse ECs without ACE2 expression explains the lack of vascular hemorrhage in COVID-19 patients and indicates that the endothelium is not a primary target of SARS-CoV-2 infection. These findings are consistent with SARS-CoV-2 indirectly activating EC programs that regulate thrombosis and endotheliitis in COVID-19 patients and focus strategies on therapeutically targeting epithelial and inflammatory responses that activate the endothelium or initiate limited ACE2-independent EC infection. IMPORTANCE SARS-CoV-2 infects pulmonary epithelial cells through ACE2 receptors and causes ARDS. COVID-19 causes progressive respiratory failure resulting from diffuse alveolar damage and systemic coagulopathy, thrombosis, and capillary inflammation that tie alveolar responses to EC dysfunction. This has prompted theories that SARS-CoV-2 directly infects ECs through ACE2 receptors, yet SARS-CoV-2 antigen has not been colocalized with ECs and prior studies indicate that ACE2 colocalizes with alveolar epithelial cells and vascular smooth muscle cells, not ECs. Here, we demonstrate that primary human ECs derived from lung, kidney, heart, brain, and umbilical veins require expression of recombinant ACE2 receptors in order to be infected by SARS-CoV-2. However, SARS-CoV-2 lytically infects ACE2-ECs and elicits procoagulative and inflammatory responses observed in COVID-19 patients. These findings suggest a novel mechanism of COVID-19 pathogenesis resulting from indirect EC activation, or infection of a small subset of ECs by an ACE2-independent mechanism, that transforms rationales and targets for therapeutic intervention.

scholarly journals Recombinant ACE2 Expression is Required for SARS-CoV-2 to Infect Primary Human Endothelial Cells and Induce Inflammatory and Procoagulative Responses

2020 ◽  
Author(s):  
Jonas Nascimento Conde ◽  
William Schutt ◽  
Elena E. Gorbunova ◽  
Erich R. Mackow
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Responses ◽  
Diffuse Alveolar Damage ◽  
Umbilical Vein ◽  
Alveolar Epithelial Cells ◽  
Small Subset ◽  
Upper Respiratory Tract ◽  
Alveolar Epithelial ◽  
Progressive Respiratory Failure ◽  
Ciliated Epithelial Cells

AbstractSARS-CoV-2 causes COVID-19, an acute respiratory distress syndrome (ARDS) characterized by pulmonary edema, viral pneumonia, multiorgan dysfunction, coagulopathy and inflammation. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) receptors to infect and damage ciliated epithelial cells in the upper respiratory tract. In alveoli, gas exchange occurs across an epithelial-endothelial barrier that ties respiration to endothelial cell (EC) regulation of edema, coagulation and inflammation. How SARS-CoV-2 dysregulates vascular functions to cause ARDS in COVID-19 patients remains an enigma focused on dysregulated EC responses. Whether SARS-CoV-2 directly or indirectly affects functions of the endothelium remains to be resolved and critical to understanding SARS-CoV-2 pathogenesis and therapeutic targets. We demonstrate that primary human ECs lack ACE2 receptors at protein and RNA levels, and that SARS-CoV-2 is incapable of directly infecting ECs derived from pulmonary, cardiac, brain, umbilical vein or kidney tissues. In contrast, pulmonary ECs transduced with recombinant ACE2 receptors are infected by SARS-CoV-2 and result in high viral titers (∼1×107/ml), multinucleate syncytia and EC lysis. SARS-CoV-2 infection of ACE2-expressing ECs elicits procoagulative and inflammatory responses observed in COVID-19 patients. The inability of SARS-CoV-2 to directly infect and lyse ECs without ACE2 expression explains the lack of vascular hemorrhage in COVID-19 patients and indicates that the endothelium is not a primary target of SARS-CoV-2 infection. These findings are consistent with SARS-CoV-2 indirectly activating EC programs that regulate thrombosis and endotheliitis in COVID-19 patients, and focus strategies on therapeutically targeting epithelial and inflammatory responses that activate the endothelium or initiate limited ACE2 independent EC infection.ImportanceSARS-CoV-2 infects pulmonary epithelial cells through ACE2 receptors and causes ARDS. COVID-19 causes progressive respiratory failure resulting from diffuse alveolar damage and systemic coagulopathy, thrombosis and capillary inflammation that tie alveolar responses to EC dysfunction. This has prompted theories that SARS-CoV-2 directly infects ECs through ACE2 receptors, yet SARS-CoV-2 antigen has not been co-localized with ECs and prior studies indicate that ACE2 co-localizes with alveolar epithelial cells and vascular smooth muscle cells, not ECs. Here we demonstrate that primary human ECs derived from lung, kidney, heart, brain and umbilical veins require expression of recombinant ACE2 receptors in order to be infected by SARS-CoV-2. However, SARS-CoV-2 lytically infects ACE2-ECs and elicits procoagulative and inflammatory responses observed in COVID-19 patients. These findings suggest a novel mechanism of COVID-19 pathogenesis resulting from indirect EC activation, or infection of a small subset of ECs by an ACE2 independent mechanism, that transform rationales and targets for therapeutic intervention.

scholarly journals Mevastatin-Induced AP-1-Dependent HO-1 Expression Suppresses Vascular Cell Adhesion Molecule-1 Expression and Monocyte Adhesion on Human Pulmonary Alveolar Epithelial Cells Challenged with TNF-α

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 381
Author(s):  
Chuen-Mao Yang ◽  
Chih-Chung Lin ◽  
Chien-Chung Yang ◽  
Rou-Ling Cho ◽  
Li-Der Hsiao
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Inflammatory Responses ◽  
Pulmonary Inflammation ◽  
Alveolar Epithelial Cells ◽  
Tanshinone Iia ◽  
Vascular Cell Adhesion ◽  
Vascular Cell ◽  
Alveolar Epithelial ◽  
P38α Mapk

Mevastatin (MVS) has been previously shown to induce heme oxygenase (HO)-1 expression through Nox/ROS-dependent PDGFRα/PI3K/Akt/Nrf2/ARE axis in human pulmonary alveolar epithelial cells (HPAEpiCs). However, alternative signaling pathways might involve in MVS-induced HO-1 expression. We found that tumor necrosis factor α (TNFα) induced vascular cell adhesion protein 1 (VCAM-1) expression and NF-κB p65 phosphorylation which were attenuated by pretreatment with MVS via up-regulation of HO-1, determined by Western blot and real-time qPCR. TNFα-induced VCAM-1 expression was attenuated by an NF-κB inhibitor, Bay117082. The inhibitory effects of MVS were reversed by tin protoporphyrin (SnPP)IX (an inhibitor of HO-1 activity). In addition, pretreatment with the inhibitor of pan-Protein kinase C (PKC) (GF109203X), PKCα (Gö6983), Pyk2 (PF431396), p38α MAPK (SB202190), JNK1/2 (SP600125), or AP-1 (Tanshinone IIA), and transfection with their respective siRNAs abolished MVS-induced HO-1 expression in HPAEpiCs. c-Jun (one of AP-1 subunits) was activated by PKCα, Pyk2, p38α MAPK, and JNK1/2, which turned on the transcription of the homx1 gene. The interaction between c-Jun and HO-1 promoter was confirmed by a chromatin immunoprecipitation (ChIP) assay, which was attenuated by these pharmacological inhibitors. These results suggested that MVS induces AP-1/HO-1 expression via PKCα/Pyk2/p38α MAPK- or JNK1/2-dependent c-Jun activation, which further binds with AP-1-binding site on HO-1 promoter and suppresses the TNFα-mediated inflammatory responses in HPAEpiCs. Thus, upregulation of the AP-1/HO-1 system by MVS exerts a potentially therapeutic strategy to protect against pulmonary inflammation.

DNA microarray analysis of gene expression in alveolar epithelial cells in response to TNFα, LPS, and cyclic stretch

2004 ◽  
Vol 19 (3) ◽  
pp. 331-342 ◽  
Author(s):  
C.C. dos Santos ◽  
B. Han ◽  
C.F. Andrade ◽  
X. Bai ◽  
S. Uhlig ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Inflammatory Responses ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Parenchymal Cell ◽  
Gene Array ◽  
Alveolar Epithelial Cells ◽  
Cyclic Stretch ◽  
Alveolar Epithelial

Recent evidence suggests that alveolar epithelial cells (AECs) may contribute to the development, propagation, and resolution of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Proinflammatory cytokines, pathogen products, and injurious mechanical ventilation are important contributors of excessive inflammatory responses in the lung. In the present study, we used cDNA microarrays to define the gene expression patterns of A549 cells (an AEC line) in the early stages of three models of pulmonary parenchymal cell activation: cells treated with tumor necrosis factor-α (TNFα) (20 ng/ml), lipopolysaccharide (LPS, 1 μg/ml), or cyclic stretch (20% elongation) for either 1 h or 4 h. Differential gene expression profiles were determined by gene array analysis. TNFα induced an inflammatory response pattern, including induction of genes for chemokines, inflammatory mediators, and cell surface membrane proteins. TNFα also increased genes related to pro- and anti-apoptotic proteins, signal transduction proteins, and transcriptional factors. TNFα further induced a group of genes that may form a negative feedback loop to silence the NFκB pathway. Stimulation of AECs with mechanical stretch changed cell morphology and activated Src protein tyrosine kinase. The combination of TNFα plus stretch enhanced or attenuated expression of multiple genes. LPS decreased microfilament polymerization but had less impact on NFκB translocation and gene expression. Results from this study indicate that AECs can tailor their response to different stimuli or/and combination of stimuli and subsequently play an important role in acute inflammatory responses in the lung.

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