scholarly journals Human Immunodeficiency Viruses Pseudotyped with SARS-CoV-2 Spike Proteins Infect a Broad Spectrum of Human Cell Lines through Multiple Entry Mechanisms

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 953
Author(s):  
Chuan Xu ◽  
Annie Wang ◽  
Ke Geng ◽  
William Honnen ◽  
Xuening Wang ◽  
...  

Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2), the causative agent of coronavirus disease 19 (COVID-19), enters cells through attachment to the human angiotensin converting enzyme 2 (hACE2) via the receptor-binding domain (RBD) in the surface/spike (S) protein. Several pseudotyped viruses expressing SARS-CoV-2 S proteins are available, but many of these can only infect hACE2-overexpressing cell lines. Here, we report the use of a simple, two-plasmid, pseudotyped virus system comprising a SARS-CoV-2 spike-expressing plasmid and an HIV vector with or without vpr to investigate the SARS-CoV-2 entry event in various cell lines. When an HIV vector without vpr was used, pseudotyped SARS-CoV-2 viruses produced in the presence of fetal bovine serum (FBS) were able to infect only engineered hACE2-overexpressing cell lines, whereas viruses produced under serum-free conditions were able to infect a broader range of cells, including cells without hACE2 overexpression. When an HIV vector containing vpr was used, pseudotyped viruses were able to infect a broad spectrum of cell types regardless of whether viruses were produced in the presence or absence of FBS. Infection sensitivities of various cell types did not correlate with mRNA abundance of hACE2, TMPRSS2, or TMPRSS4. Pseudotyped SARS-CoV-2 viruses and replication-competent SARS-CoV-2 virus were equally sensitive to neutralization by an anti-spike RBD antibody in cells with high abundance of hACE2. However, the anti-spike RBD antibody did not block pseudotyped viral entry into cell lines with low abundance of hACE2. We further found that CD147 was involved in viral entry in A549 cells with low abundance of hACE2. Thus, our assay is useful for drug and antibody screening as well as for investigating cellular receptors, including hACE2, CD147, and tyrosine-protein kinase receptor UFO (AXL), for the SARS-CoV-2 entry event in various cell lines.

2018 ◽  
Vol 26 ◽  
pp. 204020661880758 ◽  
Author(s):  
Evelyn J Franco ◽  
Jaime L Rodriquez ◽  
Justin J Pomeroy ◽  
Kaley C Hanrahan ◽  
Ashley N Brown

Chikungunya virus (CHIKV) is a mosquito-borne virus that has recently emerged in the Western Hemisphere. Approved antiviral therapies or vaccines for the treatment or prevention of CHIKV infections are not available. This study aims to evaluate the antiviral activity of commercially available broad-spectrum antivirals against CHIKV. Due to host cell-specific variability in uptake and intracellular processing of drug, we evaluated the antiviral effects of each agent in three cell lines. Antiviral activities of ribavirin (RBV), interferon-alfa (IFN-α) and favipiravir (FAV) were assessed in CHIKV-infected Vero, HUH-7, and A549 cells. CHIKV-infected cells were treated with increasing concentrations of each agent for three days and viral burden was quantified by plaque assay on Vero cells. Cytotoxic effects of RBV, FAV and IFN-α were also evaluated. Antiviral activity differed depending on the cell line used for evaluation. RBV had the greatest antiviral effect in HUH-7 cells (EC50 = 2.575 µg/mL); IFN-α was most effective in A549 cells (EC50 = 4.235 IU/mL); and FAV in HUH-7 cells (EC50 = 20.00 μg/mL). The results of our study show FAV and IFN-α are the most promising candidates, as their use led to substantial reductions in viral burden at clinically achievable concentrations in two human-derived cell lines. FAV is an especially attractive candidate for further investigation due to its oral bioavailability. These findings also highlight the importance of cell line selection for preclinical drug trials.


2021 ◽  
Vol 2 (4) ◽  
pp. 100818
Author(s):  
Madeleine Eichler ◽  
Ebru Aksi ◽  
Josef Pfeilschifter ◽  
Gergely Imre

2017 ◽  
Vol 33 (8) ◽  
pp. 646-654 ◽  
Author(s):  
Mahmoud Abudayyak ◽  
Tuba Altincekic Gurkaynak ◽  
Gül Özhan

Cobalt oxide (Co3O4) nanoparticles have applications in nanomedicine and nanotechnology; therefore, any possible adverse effects require thorough investigation. The present study investigated the effects of Co3O4 nanoparticles on four different cell lines: liver, HepG2 hepatocellular carcinoma cells; lung, A549 lung carcinoma cells; gastrointestinal, Caco-2 colorectal adenocarcinoma cells; and nervous system, SH-SY5Y neuroblastoma cells. A difference was observed in cell sensitivity toward Co3O4 nanoparticles. Co3O4 nanoparticles were taken up by all the cell types. However, no cell death was observed in HepG2, Caco-2, or SH-SY5Y cells; only A549 cells showed cytotoxicity at relatively high exposure concentrations. Co3O4 nanoparticles did not induce DNA damage or apoptosis in the cell lines tested except in A549. Interestingly, Co3O4 nanoparticles induced cellular oxidative damage in all cell types except Caco-2, resulting in increased malondialdehyde and 8-hydroxydeoxyguanosine levels and decreased glutathione levels. According to our results, it could be indicated that high concentrations of Co3O4 nanoparticles affected the pulmonary system but were unlikely to affect the liver, nervous system, or gastrointestinal system. Co3O4 nanoparticles might be safely used for industrial, commercial, and nanomedical applications if dose rates are adjusted depending on the route of exposure. However, further in vivo and in vitro studies are required to confirm the safety of Co3O4 nanoparticles.


2002 ◽  
Vol 282 (6) ◽  
pp. L1339-L1348 ◽  
Author(s):  
Joachim J. Ubl ◽  
Zoryana V. Grishina ◽  
Tatiana K. Sukhomlin ◽  
Tobias Welte ◽  
Fariba Sedehizade ◽  
...  

Protease-activated receptor-2 (PAR-2) plays a role in inflammatory reactions in airway physiology. Proteases cleaving the extracellular NH2 terminus of receptors activate or inactivate PAR, thus possessing a therapeutic potential. Using RT-PCR and immunocytochemistry, we show PAR-2 in human airway epithelial cell lines human bronchial epithelial (HBE) and A549. Functional expression of PAR-2 was confirmed by Ca2+imaging studies using the receptor agonist protease trypsin. The effect was abolished by soybean trypsin inhibitor and mimicked by the specific PAR-2 peptide agonist SLIGKV. Amplitude and duration of PAR-2-elicited Ca2+ response in HBE and A549 cells depend on concentration and time of agonist superfusion. The response is partially pertussis toxin (PTX) insensitive, abolished by the phospholipase C inhibitor U-73122, and diminished by the inositol 1,4,5-trisphosphate receptor antagonist 2-aminoethoxydiphenyl borate. Cathepsin G altered neither the resting Ca2+ level nor PAR-2-elicited Ca2+response. Thermolysin, a prototypic bacterial metalloprotease, induced a dose-dependent Ca2+ response in HBE, but not A549, cells. In both cell lines, thermolysin abolished the response to a subsequent trypsin challenge but not to SLIGKV. Thus different epithelial cell types express different PAR-2 with identical responses to physiological stimuli (trypsin, SLIGKV) but different sensitivity to modifying proteases, such as thermolysin.


2021 ◽  
Author(s):  
Li Wang ◽  
Xiaoyu Fan ◽  
Gaston Bonenfant ◽  
Dan Cui ◽  
Jaber Hossain ◽  
...  

AbstractCoinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other viruses is inevitable as the COVID-19 pandemic continues. This study aimed to evaluate cell lines commonly used in virus diagnosis and isolation for their susceptibility to SARS-CoV-2. While multiple kidney cell lines from monkeys were susceptible and permissive to SARS-CoV-2, many cell types derived from human, dog, mink, cat, mouse, or chicken were not. Analysis of MDCK cells, which are most commonly used for surveillance and study of influenza viruses, demonstrated that they were insusceptible to SARS-CoV-2 and that the cellular barrier to productive infection was due to low expression level of the angiotensin converting enzyme 2 (ACE2) receptor and lower receptor affinity to SARS-CoV-2 spike, which could be overcome by over-expression of canine ACE2 in trans. Moreover, SARS-CoV-2 cell tropism did not appear to be affected by a D614G mutation in the spike protein.


2020 ◽  
Author(s):  
Carlos Ramirez Alvarez ◽  
Ashwini Kumar Sharma ◽  
Carmon Kee ◽  
Leonie Thomas ◽  
Steeve Boulant ◽  
...  

AbstractCOVID-19 outbreak is the biggest threat to human health in recent history. Currently, there are over 1.5 million related deaths and 75 million people infected around the world (as of 22/12/2020). The identification of virulence factors which determine disease susceptibility and severity in different cell types remains an essential challenge. The serine protease TMPRSS2 has been shown to be important for S protein priming and viral entry, however, little is known about its regulation. SPINT2 is a member of the family of Kunitz type serine protease inhibitors and has been shown to inhibit TMPRSS2. Here, we explored the existence of a co-regulation between SPINT2/TMPRSS2 and found a tightly regulated protease/inhibitor expression balance across tissues. We found that SPINT2 negatively correlates with SARS-CoV-2 expression in Calu-3 and Caco-2 cell lines and was down-regulated in secretory cells from COVID-19 patients. We validated our findings using Calu-3 cell lines and observed a strong increase in viral load after SPINT2 knockdown. Additionally, we evaluated the expression of SPINT2 in datasets from comorbid diseases using bulk and scRNA-seq data. We observed its down-regulation in colon, kidney and liver tumors as well as in alpha pancreatic islets cells from diabetes Type 2 patients, which could have implications for the observed comorbidities in COVID-19 patients suffering from chronic diseases.


2021 ◽  
Vol 17 (6) ◽  
pp. e1009687
Author(s):  
Carlos Ramirez Alvarez ◽  
Carmon Kee ◽  
Ashwini Kumar Sharma ◽  
Leonie Thomas ◽  
Florian I. Schmidt ◽  
...  

COVID-19 outbreak is the biggest threat to human health in recent history. Currently, there are over 1.5 million related deaths and 75 million people infected around the world (as of 22/12/2020). The identification of virulence factors which determine disease susceptibility and severity in different cell types remains an essential challenge. The serine protease TMPRSS2 has been shown to be important for S protein priming and viral entry, however, little is known about its regulation. SPINT2 is a member of the family of Kunitz type serine protease inhibitors and has been shown to inhibit TMPRSS2. Here, we explored the existence of a co-regulation between SPINT2/TMPRSS2 and found a tightly regulated protease/inhibitor expression balance across tissues. We found that SPINT2 negatively correlates with SARS-CoV-2 expression in Calu-3 and Caco-2 cell lines and was down-regulated in secretory cells from COVID-19 patients. We validated our findings using Calu-3 cell lines and observed a strong increase in viral load after SPINT2 knockdown, while overexpression lead to a drastic reduction of the viral load. Additionally, we evaluated the expression of SPINT2 in datasets from comorbid diseases using bulk and scRNA-seq data. We observed its down-regulation in colon, kidney and liver tumors as well as in alpha pancreatic islets cells from diabetes Type 2 patients, which could have implications for the observed comorbidities in COVID-19 patients suffering from chronic diseases.


Author(s):  
Irene Lui ◽  
Xin X. Zhou ◽  
Shion A. Lim ◽  
Susanna K. Elledge ◽  
Paige Solomon ◽  
...  

AbstractA serious public health crisis is currently unfolding due to the SARS-CoV-2 pandemic. SARS-CoV-2 viral entry depends on an interaction between the receptor binding domain of the trimeric viral Spike protein (Spike-RBD) and the dimeric human angiotensin converting enzyme 2 (ACE2) receptor. While it is clear that strategies to block the Spike/ACE2 interaction are promising as anti-SARS-CoV-2 therapeutics, our current understanding is insufficient for the rational design of maximally effective therapeutic molecules. Here, we investigated the mechanism of Spike/ACE2 interaction by characterizing the binding affinity and kinetics of different multimeric forms of recombinant ACE2 and Spike-RBD domain. We also engineered ACE2 into a split Nanoluciferase-based reporter system to probe the conformational landscape of Spike-RBDs in the context of the Spike trimer. Interestingly, a dimeric form of ACE2, but not monomeric ACE2, binds with high affinity to Spike and blocks viral entry in pseudotyped virus and live SARS-CoV-2 virus neutralization assays. We show that dimeric ACE2 interacts with an RBD on Spike with limited intra-Spike avidity, which nonetheless contributes to the affinity of this interaction. Additionally, we demonstrate that a proportion of Spike can simultaneously interact with multiple ACE2 dimers, indicating that more than one RBD domain in a Spike trimer can adopt an ACE2-accessible “up” conformation. Our findings have significant implications on the design strategies of therapeutic molecules that block the Spike/ACE2 interaction. The constructs we describe are freely available to the research community as molecular tools to further our understanding of SARS-CoV-2 biology.


2020 ◽  
Vol 20 (10) ◽  
pp. 1241-1249
Author(s):  
Hong-Chuan Liu ◽  
Li-Ming Qiao ◽  
Wei Zheng ◽  
Zhao-Bao Xiang ◽  
Hai-Sheng Chen ◽  
...  

Background: Rabdosia japonica has been historically used in China as a popular folk medicine for the treatment of cancer, hepatitis, and gastricism. Glaucocalyxin A (GLA), an ent-kaurene diterpene isolated from Rabdosia japonica, is one of the main active ingredients showing potent inhibitory effects against several types of tumor cells. To the best of our knowledge, studies regarding the structural modification and Structure- Activity Relations (SAR) of this compound have not yet been reported. Objective: The aim of this study was to discover more potent derivatives of GLA and investigate their SAR and cytotoxicity mechanisms. Methods: Novel 7-O- and 14-O-derivatives of GLA were synthesized by condensation of acids or acyl chloride. The anti-tumor activities of these derivatives against various human cancer cell lines were evaluated in vitro by MTT assays. Apoptosis assays of compound 17 (7,14-diacylation product) were performed on A549 and HL-60 cells by flow cytometry and TUNNEL. The acute toxicity of this compound was tested on mice, at the dose of 300mg per kg body weight. Results: Seventeen novel 7-O- and 14-O-derivatives of GLA (1-17) were synthesized. These compounds showed potent cytotoxicity against the tested cancer cell lines, and almost all of them were found to be more cytotoxic than GLA and oridonin. Of the synthesized derivatives, compound 17 presented the greatest cytotoxicity, with IC50 values of 0.26μM and 1.10μM in HL-60 and CCRF-CEM cells, respectively. Furthermore, this compound induced weak apoptosis of A549 cells but showed great potential in stimulating the apoptosis of HL- 60 cells. Acute toxicity assays indicated that compound 17 is relatively safer. Conclusion: The results reported herein indicate that the synthesized GLA derivatives exhibited greater cytotoxicity against leukemia cells than against other types of tumors. In particular, 7,14-diacylation product of GLA was found to be an effective anti-tumor agent. However, the cytotoxicity mechanism of this product in A549 cells is expected to be different than that in other tumor cell lines. Further research is needed to confirm this hypothesis.


2020 ◽  
Vol 11 ◽  
Author(s):  
Dimitris G. Placantonakis ◽  
Maria Aguero-Rosenfeld ◽  
Abdallah Flaifel ◽  
John Colavito ◽  
Kenneth Inglima ◽  
...  

Neurologic manifestations of the novel coronavirus SARS-CoV-2 infection have received wide attention, but the mechanisms remain uncertain. Here, we describe computational data from public domain RNA-seq datasets and cerebrospinal fluid data from adult patients with severe COVID-19 pneumonia that suggest that SARS-CoV-2 infection of the central nervous system is unlikely. We found that the mRNAs encoding the ACE2 receptor and the TMPRSS2 transmembrane serine protease, both of which are required for viral entry into host cells, are minimally expressed in the major cell types of the brain. In addition, CSF samples from 13 adult encephalopathic COVID-19 patients diagnosed with the viral infection via nasopharyngeal swab RT-PCR did not show evidence for the virus. This particular finding is robust for two reasons. First, the RT-PCR diagnostic was validated for CSF studies using stringent criteria; and second, 61% of these patients had CSF testing within 1 week of a positive nasopharyngeal diagnostic test. We propose that neurologic sequelae of COVID-19 are not due to SARS-CoV-2 meningoencephalitis and that other etiologies are more likely mechanisms.


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