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1.
Am J Respir Cell Mol Biol ; 66(3): 323-336, 2022 03.
Article in English | MEDLINE | ID: covidwho-1714501

ABSTRACT

Administration of high concentrations of oxygen (hyperoxia) is one of few available options to treat acute hypoxemia-related respiratory failure, as seen in the current coronavirus disease (COVID-19) pandemic. Although hyperoxia can cause acute lung injury through increased production of superoxide anion (O2•-), the choice of high-concentration oxygen administration has become a necessity in critical care. The objective of this study was to test the hypothesis that UCP2 (uncoupling protein 2) has a major function of reducing O2•- generation in the lung in ambient air or in hyperoxia. Lung epithelial cells and wild-type; UCP2-/-; or transgenic, hTrx overexpression-bearing mice (Trx-Tg) were exposed to hyperoxia and O2•- generation was measured by using electron paramagnetic resonance, and lung injury was measured by using histopathologic analysis. UCP2 expression was analyzed by using RT-PCR analysis, Western blotting analysis, and RNA interference. The signal transduction pathways leading to loss of UCP2 expression were analyzed by using IP, phosphoprotein analysis, and specific inhibitors. UCP2 mRNA and protein expression were acutely decreased in hyperoxia, and these decreases were associated with a significant increase in O2•- production in the lung. Treatment of cells with rhTrx (recombinant human thioredoxin) or exposure of Trx-Tg mice prevented the loss of UCP2 protein and decreased O2•- generation in the lung. Trx is also required to maintain UCP2 expression in normoxia. Loss of UCP2 in UCP2-/- mice accentuated lung injury in hyperoxia. Trx activates the MKK4-p38MAPK (p38 mitogen-activated protein kinase)-PGC1α (PPARγ [peroxisome proliferator-activated receptor γ] coactivator 1α) pathway, leading to rescue of UCP2 and decreased O2•- generation in hyperoxia. Loss of UCP2 in hyperoxia is a major mechanism of O2•- production in the lung in hyperoxia. rhTrx can protect against lung injury in hyperoxia due to rescue of the loss of UCP2.


Subject(s)
Lung/metabolism , Oxygen/metabolism , Thioredoxins/metabolism , Uncoupling Protein 2/metabolism , Animals , COVID-19/metabolism , COVID-19/therapy , Cell Line , Humans , Hyperoxia/metabolism , Lung/cytology , MAP Kinase Kinase 4/genetics , MAP Kinase Kinase 4/metabolism , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Oxygen/toxicity , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/genetics , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Phosphorylation , Signal Transduction , Superoxides/metabolism , Thioredoxins/genetics , Thioredoxins/pharmacology , Uncoupling Protein 2/genetics , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
2.
Stem Cell Reports ; 17(3): 538-555, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1692861

ABSTRACT

To date, the direct causative mechanism of SARS-CoV-2-induced endotheliitis remains unclear. Here, we report that human ECs barely express surface ACE2, and ECs express less intracellular ACE2 than non-ECs of the lungs. We ectopically expressed ACE2 in hESC-ECs to model SARS-CoV-2 infection. ACE2-deficient ECs are resistant to the infection but are more activated than ACE2-expressing ones. The virus directly induces endothelial activation by increasing monocyte adhesion, NO production, and enhanced phosphorylation of p38 mitogen-associated protein kinase (MAPK), NF-κB, and eNOS in ACE2-expressing and -deficient ECs. ACE2-deficient ECs respond to SARS-CoV-2 through TLR4 as treatment with its antagonist inhibits p38 MAPK/NF-κB/ interleukin-1ß (IL-1ß) activation after viral exposure. Genome-wide, single-cell RNA-seq analyses further confirm activation of the TLR4/MAPK14/RELA/IL-1ß axis in circulating ECs of mild and severe COVID-19 patients. Circulating ECs could serve as biomarkers for indicating patients with endotheliitis. Together, our findings support a direct role for SARS-CoV-2 in mediating endothelial inflammation in an ACE2-dependent or -independent manner.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Models, Biological , SARS-CoV-2/physiology , Toll-Like Receptor 4/metabolism , Angiotensin-Converting Enzyme 2/genetics , COVID-19/pathology , COVID-19/virology , Endothelial Cells/cytology , Endothelial Cells/metabolism , Gene Expression Profiling , Human Umbilical Vein Endothelial Cells , Humans , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , NF-kappa B/antagonists & inhibitors , NF-kappa B/genetics , NF-kappa B/metabolism , Pluripotent Stem Cells/cytology , Pluripotent Stem Cells/metabolism , SARS-CoV-2/isolation & purification , Severity of Illness Index , Single-Cell Analysis , Toll-Like Receptor 4/antagonists & inhibitors , Toll-Like Receptor 4/genetics , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
3.
Expert Rev Mol Med ; 24: e4, 2022 01 21.
Article in English | MEDLINE | ID: covidwho-1641781

ABSTRACT

Viruses completely rely on the energy and metabolic systems of host cells for life activities. Viral infections usually lead to cytopathic effects and host diseases. To date, there are still no specific clinical vaccines or drugs against most viral infections. Therefore, understanding the molecular and cellular mechanisms of viral infections is of great significance to prevent and treat viral diseases. A variety of viral infections are related to the p38 MAPK signalling pathway, and p38 is an important host factor in virus-infected cells. Here, we introduce the different signalling pathways of p38 activation and then summarise how different viruses induce p38 phosphorylation. Finally, we provide a general summary of the effect of p38 activation on virus replication. Our review provides integrated data on p38 activation and viral infections and describes the potential application of targeting p38 as an antiviral strategy.


Subject(s)
Virus Diseases , p38 Mitogen-Activated Protein Kinases , Humans , MAP Kinase Signaling System , Phosphorylation , Virus Replication , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
4.
Am J Respir Cell Mol Biol ; 66(3): 323-336, 2022 03.
Article in English | MEDLINE | ID: covidwho-1566427

ABSTRACT

Administration of high concentrations of oxygen (hyperoxia) is one of few available options to treat acute hypoxemia-related respiratory failure, as seen in the current coronavirus disease (COVID-19) pandemic. Although hyperoxia can cause acute lung injury through increased production of superoxide anion (O2•-), the choice of high-concentration oxygen administration has become a necessity in critical care. The objective of this study was to test the hypothesis that UCP2 (uncoupling protein 2) has a major function of reducing O2•- generation in the lung in ambient air or in hyperoxia. Lung epithelial cells and wild-type; UCP2-/-; or transgenic, hTrx overexpression-bearing mice (Trx-Tg) were exposed to hyperoxia and O2•- generation was measured by using electron paramagnetic resonance, and lung injury was measured by using histopathologic analysis. UCP2 expression was analyzed by using RT-PCR analysis, Western blotting analysis, and RNA interference. The signal transduction pathways leading to loss of UCP2 expression were analyzed by using IP, phosphoprotein analysis, and specific inhibitors. UCP2 mRNA and protein expression were acutely decreased in hyperoxia, and these decreases were associated with a significant increase in O2•- production in the lung. Treatment of cells with rhTrx (recombinant human thioredoxin) or exposure of Trx-Tg mice prevented the loss of UCP2 protein and decreased O2•- generation in the lung. Trx is also required to maintain UCP2 expression in normoxia. Loss of UCP2 in UCP2-/- mice accentuated lung injury in hyperoxia. Trx activates the MKK4-p38MAPK (p38 mitogen-activated protein kinase)-PGC1α (PPARγ [peroxisome proliferator-activated receptor γ] coactivator 1α) pathway, leading to rescue of UCP2 and decreased O2•- generation in hyperoxia. Loss of UCP2 in hyperoxia is a major mechanism of O2•- production in the lung in hyperoxia. rhTrx can protect against lung injury in hyperoxia due to rescue of the loss of UCP2.


Subject(s)
Lung/metabolism , Oxygen/metabolism , Thioredoxins/metabolism , Uncoupling Protein 2/metabolism , Animals , COVID-19/metabolism , COVID-19/therapy , Cell Line , Humans , Hyperoxia/metabolism , Lung/cytology , MAP Kinase Kinase 4/genetics , MAP Kinase Kinase 4/metabolism , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Oxygen/toxicity , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/genetics , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Phosphorylation , Signal Transduction , Superoxides/metabolism , Thioredoxins/genetics , Thioredoxins/pharmacology , Uncoupling Protein 2/genetics , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
5.
Virus Res ; 280: 197901, 2020 04 15.
Article in English | MEDLINE | ID: covidwho-833197

ABSTRACT

Transmissible gastroenteritis virus (TGEV) primarily replicates in intestinal epithelial cells and causes severe damage to host cells, resulting in diarrhea. Surface NHE3 serves as the key regulatory site controlling electroneutral Na+ absorption. In this study, our results showed that the surface NHE3 content was significantly reduced following TGEV infection, whereas the total level of protein expression was not significantly changed, and NHE3 activity gradually decreased with prolonged infection time. We then inhibited SGLT1 expression by lentiviral interference and drug inhibition, respectively. Inhibition studies showed that the level of phosphorylation of the downstream key proteins, MAPKAPK-2 and EZRIN, in the SGLT1-mediated p38MAPK/AKt2 signaling pathway was significantly increased. The surface NHE3 expression was also significantly increased, and NHE3 activity was also significantly enhanced. These results demonstrate that a TGEV infection can inhibit NHE3 translocation and attenuates sodium-hydrogen exchange activity via the SGLT1-mediated p38MAPK/AKt2 signaling pathway, affecting cellular electrolyte absorption leading to diarrhea.


Subject(s)
Enterocytes/virology , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Sodium-Glucose Transporter 1/genetics , Sodium-Hydrogen Exchanger 3/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , Animals , Cell Line , Proto-Oncogene Proteins c-akt/genetics , Sodium-Glucose Transporter 1/metabolism , Sodium-Hydrogen Exchanger 3/genetics , Swine , Transmissible gastroenteritis virus , p38 Mitogen-Activated Protein Kinases/genetics
6.
FEBS J ; 287(17): 3651-3655, 2020 09.
Article in English | MEDLINE | ID: covidwho-10071

ABSTRACT

The recent emergence of COVID-19 has resulted in a worldwide crisis, with large populations locked down and transportation links severed. While approximately 80% of infected individuals have minimal symptoms, around 15-20% need to be hospitalized, greatly stressing global healthcare systems. As of March 10, the death rate appears to be about 3.4%, although this number is highly stratified among different populations. Here, we focus on those individuals who have been exposed to nicotine prior to their exposure to the virus. We predict that these individuals are 'primed' to be at higher risk because nicotine can directly impact the putative receptor for the virus (ACE2) and lead to deleterious signaling in lung epithelial cells.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , COVID-19/epidemiology , Nicotine/adverse effects , Pandemics , Receptors, Nicotinic/genetics , Smoking/epidemiology , Spike Glycoprotein, Coronavirus/genetics , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/genetics , COVID-19/physiopathology , COVID-19/virology , Female , Gene Expression Regulation , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Humans , Lung/drug effects , Lung/pathology , Lung/virology , Male , Receptors, Nicotinic/metabolism , Receptors, Virus/genetics , Receptors, Virus/metabolism , SARS-CoV-2/pathogenicity , Severity of Illness Index , Sex Factors , Signal Transduction , Smoking/genetics , Smoking/physiopathology , Spike Glycoprotein, Coronavirus/metabolism , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
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