scholarly journals The Delta variant of SARS-CoV-2 maintains high sensitivity to interferons in human lung cells

2021 ◽  
Author(s):  
Rayhane Nchioua ◽  
Annika Schundner ◽  
Susanne Klute ◽  
Sabrina Noettger ◽  
Fabian Zech ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Human Lung ◽  
Virus Production ◽  
High Sensitivity ◽  
Alveolar Type ◽  
Type I ◽  
Innate Defense ◽  
Human Lung Cells ◽  
Alpha Beta

Interferons are a major part of the anti-viral innate defense system. Successful pathogens, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), need to overcome these defenses to establish an infection. Early induction of interferons (IFNs) protects against severe coronavirus disease 2019 (COVID-19). In line with this, SARS-CoV-2 is inhibited by IFNs in vitro, and IFN-based therapies against COVID-19 are investigated in clinical trials. However, SARS-CoV-2 continues to adapt to the human population resulting in the emergence of variants characterized by increased transmission fitness and/or decreased sensitivity to preventive or therapeutic measures. It has been suggested that the efficient spread of these so-called "Variants of Concern" (VOCs) may also involve reduced sensitivity to IFNs. Here, we examined whether the four current VOCs (Alpha, Beta, Gamma and Delta) differ in replication efficiency or IFN sensitivity from an early isolate of SARS-CoV-2. All viruses replicated in a human lung cell line and in iPSC-derived alveolar type II cells (iAT2). The Delta variant showed accelerated replication kinetics and higher infectious virus production compared to the early 2020 isolate. Replication of all SARS-CoV-2 VOCs was reduced in the presence of exogenous type I, II and III IFNs. On average, the Alpha variant was the least susceptible to IFNs and the Alpha, Beta and Gamma variants show increased resistance against type III IFN. Although the Delta variant has outcompeted all other variants in humans it remained as sensitive to IFNs as an early 2020 SARS-CoV-2 isolate. This suggests that increased replication fitness rather than IFN resistance may be a reason for its dominance. Our results may help to understand changes in innate immune susceptibility of VOCs, and inform clinical trials exploring IFN-based COVID-19 therapies.

scholarly journals Grouping of Poorly Soluble Low (Cyto)Toxic Particles: Example with 15 Selected Nanoparticles and A549 Human Lung Cells

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 704
Author(s):  
Veno Kononenko ◽  
David B. Warheit ◽  
Damjana Drobne
Keyword(s):  
Human Lung ◽  
A549 Cells ◽  
Test System ◽  
Alveolar Type ◽  
In Vitro Test ◽  
Human Lung Cells ◽  
Poorly Soluble ◽  
Lysosomal System ◽  
Biological Endpoint

Poorly soluble, low (cyto)toxic particles (PSLTs) are often regarded as one group, but it is important that these particles can be further differentiated based on their bioactivity. Currently, there are no biological endpoint based groupings for inhaled nanoparticles (NPs) that would allow us to subgroup PSLTs based on their mode of action. The aim of this study was to group NPs based on their cytotoxicity and by using the in vitro response of the endo-lysosomal system as a biological endpoint. The endo-lysosomal system is a main cellular loading site for NPs. An impaired endo-lysosomal system in alveolar type II cells may have serious adverse effects on the maintenance of pulmonary surfactant homeostasis. The 15 different NPs were tested with human lung adenocarcinoma (A549) cells. The highly soluble NPs were most cytotoxic. With respect to PSLTs, only three NPs increased the cellular load of acid and phospholipid rich organelles indicating particle biopersistence. All the rest PSLTs could be regarded as low hazardous. The presented in vitro test system could serve as a fast screening tool to group particles according to their ability to interfere with lung surfactant metabolism. We discuss the applicability of the suggested test system for bringing together substances with similar modes-of-action on lung epithelium. In addition, we discuss this approach as a benchmark test for the comparative assessment of biopersistence of PSLTs.

scholarly journals Polyphosphate Reverses the Toxicity of the Quasi-Enzyme Bleomycin on Alveolar Endothelial Lung Cells In Vitro

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 750
Author(s):  
Werner E. G. Müller ◽  
Meik Neufurth ◽  
Shunfeng Wang ◽  
Heinz C. Schröder ◽  
Xiaohong Wang
Keyword(s):  
Dna Damage ◽  
Human Lung ◽  
Dna Integrity ◽  
Lung Cells ◽  
Antitumor Antibiotic ◽  
Cell Toxicity ◽  
Inorganic Polyphosphate ◽  
Human Lung Cells ◽  
Anti Cancer

The anti-cancer antitumor antibiotic bleomycin(s) (BLM) induces athyminic sites in DNA after its activation, a process that results in strand splitting. Here, using A549 human lung cells or BEAS-2B cells lunc cells, we show that the cell toxicity of BLM can be suppressed by addition of inorganic polyphosphate (polyP), a physiological polymer that accumulates and is released from platelets. BLM at a concentration of 20 µg ml−1 causes a decrease in cell viability (by ~70%), accompanied by an increased DNA damage and chromatin expansion (by amazingly 6-fold). Importantly, the BLM-caused effects on cell growth and DNA integrity are substantially suppressed by polyP. In parallel, the enlargement of the nuclei/chromatin in BLM-treated cells (diameter, 20–25 µm) is normalized to ~12 µm after co-incubation of the cells with BLM and polyP. A sequential application of the drugs (BLM for 3 days, followed by an exposure to polyP) does not cause this normalization. During co-incubation of BLM with polyP the gene for the BLM hydrolase is upregulated. It is concluded that by upregulating this enzyme polyP prevents the toxic side effects of BLM. These data might also contribute to an application of BLM in COVID-19 patients, since polyP inhibits binding of SARS-CoV-2 to cellular ACE2.

Pathobiological Effects of Fibers and Tobacco-Related Chemicals in Human Lung Cells In Vitro

1989 ◽  
pp. 103-117
Author(s):  
C. C. Harris ◽  
J. C. Willey ◽  
N. Matsukura ◽  
J. F. Lechner ◽  
M. Miyashita ◽  
...  
Keyword(s):  
Human Lung ◽  
Lung Cells ◽  
Human Lung Cells

Mechanisms and regulation of ion transport in adult mammalian alveolar type II pneumocytes

1991 ◽  
Vol 261 (5) ◽  
pp. C727-C738 ◽  
Author(s):  
S. Matalon
Keyword(s):  
Epithelial Transport ◽  
Cultured Cells ◽  
Basolateral Membrane ◽  
Alveolar Epithelium ◽  
Alveolar Type ◽  
Type I ◽  
Type Ii ◽  
Epithelial Lining ◽  
Epithelial Lining Fluid

The adult alveolar epithelium consists of type I and type II (ATII) pneumocytes that form a tight barrier, which severely restricts the entry of lipid-insoluble molecules from the interstitial to the alveolar space. Current in vivo and in vitro evidence indicates that the alveolar epithelium is also an absorptive epithelium, capable of transporting Na+ from the alveolar lumen, which is bathed by a small amount of epithelial lining fluid, to the interstitial space. The in situ localization of Na(+)-K(+)-ATPase activity in ATII cells and the fact that these cells are involved in a number of crucial functions, such as surfactant secretion and alveolar remodeling after injury, led investigators to examine their transport characteristics. Radioactive flux studies, in both freshly isolated and cultured cells, and bioelectric measurements in ATII cells grown on porous supports indicate that they transport Na+ according to the Koefoed-Johnsen and Ussing model of epithelial transport. Na+ enters the apical membrane, because of the favorable electrochemical gradient, through Na+ cotransporters, a Na(+)-H+ antiport, and cation channels and is pumped across the basolateral membrane by a ouabain-sensitive Na(+)-K+ pump. Na+ transport is enhanced by substances that increase intracellular adenosine 3',5'-cyclic monophosphate. In addition to Na+ transporters, ATII cells contain several transporters that regulate their intracellular pH, including a H(+)-ATPase, which may explain the low pH of the epithelial lining fluid. The absorptive properties of ATII cells may play an important role in regulating the degree of alveolar fluid in health and disease.

scholarly journals SARS-CoV-2 Is Restricted by Zinc Finger Antiviral Protein despite Preadaptation to the Low-CpG Environment in Humans

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Rayhane Nchioua ◽  
Dorota Kmiec ◽  
Janis A. Müller ◽  
Carina Conzelmann ◽  
Rüdiger Groß ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Human Lung ◽  
Lung Cells ◽  
Type I ◽  
Antiviral Protein ◽  
Viral Pathogen ◽  
Cpg Dinucleotides ◽  
Human Lung Cells ◽  
Ifn Γ ◽  
Horseshoe Bat

ABSTRACT Recent evidence shows that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is sensitive to interferons (IFNs). However, the most effective types of IFNs and the underlying antiviral effectors remain to be defined. Here, we show that zinc finger antiviral protein (ZAP), which preferentially targets CpG dinucleotides in viral RNA sequences, restricts SARS-CoV-2. We further demonstrate that ZAP and its cofactors KHNYN and TRIM25 are expressed in human lung cells. Type I, II, and III IFNs all strongly inhibited SARS-CoV-2 and further induced ZAP expression. Comprehensive sequence analyses revealed that SARS-CoV-2 and its closest relatives from horseshoe bats showed the strongest CpG suppression among all known human and bat coronaviruses, respectively. Nevertheless, endogenous ZAP expression restricted SARS-CoV-2 replication in human lung cells, particularly upon treatment with IFN-α or IFN-γ. Both the long and the short isoforms of human ZAP reduced SARS-CoV-2 RNA expression levels, but the former did so with greater efficiency. Finally, we show that the ability to restrict SARS-CoV-2 is conserved in ZAP orthologues of the reservoir bat and potential intermediate pangolin hosts of human coronaviruses. Altogether, our results show that ZAP is an important effector of the innate response against SARS-CoV-2, although this pandemic pathogen emerged from zoonosis of a coronavirus that was preadapted to the low-CpG environment in humans. IMPORTANCE Although interferons inhibit SARS-CoV-2 and have been evaluated for treatment of coronavirus disease 2019 (COVID-19), the most effective types and antiviral effectors remain to be defined. Here, we show that IFN-γ is particularly potent in restricting SARS-CoV-2 and in inducing expression of the antiviral factor ZAP in human lung cells. Knockdown experiments revealed that endogenous ZAP significantly restricts SARS-CoV-2. We further show that CpG dinucleotides which are specifically targeted by ZAP are strongly suppressed in the SARS-CoV-2 genome and that the two closest horseshoe bat relatives of SARS-CoV-2 show the lowest genomic CpG content of all coronavirus sequences available from this reservoir host. Nonetheless, both the short and long isoforms of human ZAP reduced SARS-CoV-2 RNA levels, and this activity was conserved in horseshoe bat and pangolin ZAP orthologues. Our findings indicating that type II interferon is particularly efficient against SARS-CoV-2 and that ZAP restricts this pandemic viral pathogen might promote the development of effective immune therapies against COVID-19.

scholarly journals The use of naturally occurring hybrid variants of chloramphenicol acetyltransferase to investigate subunit contacts

1981 ◽  
Vol 193 (2) ◽  
pp. 541-552 ◽  
Author(s):  
L C Packman ◽  
W V Shaw
Keyword(s):  
Chloramphenicol Acetyltransferase ◽  
Alpha Subunit ◽  
Type I ◽  
Chloramphenicol Resistance ◽  
Type Iii ◽  
Naturally Occurring ◽  
Alpha Beta ◽  
Beta 2

1. Hybrids of the tetrameric enzyme chloramphenicol acetyltransferase (EC 2.3.1.28) were formed in vivo in a strain of Escherichia coli which harbours two different plasmids, each of which normally confers chloramphenicol resistance and specifies an easily distinguished enzyme variant (type I or type III) which is composed of identical subunits. Cell-free extracts of the dual-plasmid strain were found to contain five species of active enzyme, two of which were the homomeric enzymes corresponding to the naturally occurring tetramers of the type-I (beta 4) and type-III (alpha 4) enzymes. The other three variants were judged to be the heteromeric hybrid variants (alpha 3 beta, alpha 2 beta 2, alpha beta 3). 2. The alpha 3 beta and alpha 2 beta 2 hybrids of chloramphenicol acetyltransferase were purified to homogeneity by combining the techniques of affinity and ion-exchange chromatography. The alpha beta 3 variant was not recovered and may be unstable in vitro. 3. The unique lysine residues that could not be modified with methyl acetimidate in each of the native homomeric enzymes were also investigated in the heteromeric tetramers. 4. Lysine-136 remains buried in each beta subunit of the parental (type I) enzyme and in each of the hybrid tetramers. Lysine-38 of each alpha subunit is similarly unreactive in the native type-III chloramphenicol acetyltransferase (alpha 4), but in the alpha 2 beta 2 hybird lysine-38 of each alpha subunit is fully exposed to solvent. Another lysine residue, fully reactive in the alpha 4 enzyme, was observed to be inaccessible to modification in the symmetrical hybrid. The results obtained for the alpha 3 beta enzyme suggest that lysine-38 in two subunits and a different lysine group (that identified in the alpha 2 beta 2 enzyme) in the third alpha subunit are buried. 5. A tentative model for the subunit interactions of chloramphenicol acetyltransferase is proposed on the basis of the results described.

Genomic responses of human lung cells exposure through a successful in vitro field deployment in Houston, Texas

2017 ◽  
Vol 280 ◽  
pp. S212
Author(s):  
Hang Nguyen ◽  
Kenneth Sexton ◽  
Lisa Smeester ◽  
Kjersti Marie Aagaard ◽  
Cynthia Do Shope ◽  
...  
Keyword(s):  
Human Lung ◽  
Lung Cells ◽  
Human Lung Cells ◽  
Field Deployment

Extravascular sources of lung angiotensin peptide synthesis in idiopathic pulmonary fibrosis

2006 ◽  
Vol 291 (5) ◽  
pp. L887-L895 ◽  
Author(s):  
Xiaopeng Li ◽  
Maria Molina-Molina ◽  
Amal Abdul-Hafez ◽  
Jose Ramirez ◽  
Anna Serrano-Mollar ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Human Lung ◽  
De Novo ◽  
Alveolar Epithelial Cells ◽  
Human Lung Cells ◽  
Normal Human

Previous work from this laboratory demonstrated de novo synthesis of angiotensin (ANG) peptides by apoptotic pulmonary alveolar epithelial cells (AEC) and by lung myofibroblasts in vitro and in bleomycin-treated rats. To determine whether these same cell types also synthesize ANG peptides de novo within the fibrotic human lung in situ, we subjected paraffin sections of normal and fibrotic (idiopathic pulmonary fibrosis, IPF) human lung to immunohistochemistry (IHC) and in situ hybridization to detect ANG peptides and angiotensinogen (AGT) mRNA. These were analyzed both alone and in combination with cell-specific markers of AEC [monoclonal antibody (MAb) MNF-116] and myofibroblasts [α-smooth muscle actin (α-SMA) MAb] and an in situ DNA end labeling (ISEL) method to detect apoptosis. In normal human lung, IHC detected AGT protein in smooth muscle underlying normal bronchi and vessels, but not elsewhere. Real-time RT-PCR and Western blotting revealed that AGT mRNA and protein were 21-fold and 3.6-fold more abundant, respectively, in IPF lung biopsies relative to biopsies of normal human lung (both P < 0.05). In IPF lung, both AGT protein and mRNA were detected in AEC that double-labeled with MAb MNF-116 and with ISEL, suggesting AGT expression by apoptotic epithelia in situ. AGT protein and mRNA also colocalized to myofibroblast foci detected by α-SMA MAb, but AGT mRNA was not detected in smooth muscle. These data are consistent with earlier data from isolated human lung cells in vitro and bleomycin-induced rat lung fibrosis models, and they suggest that apoptotic AEC and myofibroblasts constitute key sources of locally derived ANG peptides in the IPF lung.

Quantitation and characterization of leukotriene products released following immunologic stimulation of human lung cells in vitro

CHEST Journal ◽  
1983 ◽  
Vol 83 (5) ◽  
pp. 81S-82 ◽  
Author(s):  
A. G. Leitch ◽  
R. A. Lewis ◽  
E. J. Corey ◽  
K. F. Austen
Keyword(s):  
Human Lung ◽  
Lung Cells ◽  
Human Lung Cells ◽  
Stimulation Of
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