scholarly journals Plant Alkaloids Inhibit Membrane Fusion Mediated by Calcium and Fragments of MERS-CoV and SARS-CoV/SARS-CoV-2 Fusion Peptides

Biomedicines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1434
Author(s):  
Egor V. Shekunov ◽  
Svetlana S. Efimova ◽  
Natalia M. Yudintceva ◽  
Anna A. Muryleva ◽  
Vladimir V. Zarubaev ◽  
...  

To rationalize the antiviral actions of plant alkaloids, the ability of 20 compounds to inhibit calcium-mediated fusion of lipid vesicles composed of phosphatidylglycerol and cholesterol was investigated using the calcein release assay and dynamic light scattering. Piperine, tabersonine, hordenine, lupinine, quinine, and 3-isobutyl-1-methylxanthine demonstrated the most potent effects (inhibition index greater than 50%). The introduction of phosphatidylcholine into the phosphatidylglycerol/cholesterol mixture led to significant changes in quinine, hordenine, and 3-isobutyl-1-methylxanthine efficiency. Comparison of the fusion inhibitory ability of the tested alkaloids, and the results of the measurements of alkaloid-induced alterations in the physical properties of model membranes indicated a potent relationship between a decrease in the cooperativity of the phase transition of lipids and the ability of alkaloids to prevent calcium-mediated vesicle fusion. In order to use this knowledge to combat the novel coronavirus pandemic, the ability of the most effective compounds to suppress membrane fusion induced by fragments of MERS-CoV and SARS-CoV/SARS-CoV-2 fusion peptides was studied using the calcein release assay and confocal fluorescence microscopy. Piperine was shown to inhibit vesicle fusion mediated by both coronavirus peptides. Moreover, piperine was shown to significantly reduce the titer of SARS-CoV2 progeny in vitro in Vero cells when used in non-toxic concentrations.

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 361
Author(s):  
Natalya Bukreyeva ◽  
Rachel A. Sattler ◽  
Emily K. Mantlo ◽  
Timothy Wanninger ◽  
John T. Manning ◽  
...  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the novel coronavirus responsible for the ongoing COVID-19 pandemic, which has resulted in over 2.5 million confirmed cases and 170,000 deaths worldwide as of late April 2020. The pandemic currently presents major public health and economic burdens worldwide. No vaccines or therapeutics have been approved for use to treat COVID-19 cases in the United States despite the growing disease burden, thus creating an urgent need for effective treatments. The adenosine analogue remdesivir (REM) has recently been investigated as a potential treatment option, and has shown some activity in limiting SARS-CoV-2 replication. We previously reported that the IMPDH inhibitor merimepodib (MMPD) provides a dose-dependent suppression of SARS-CoV-2 replication in vitro. Here, we report that a 4-hour pre-treatment of Vero cells with 2.5µM MMPD reduces the infectious titer of SARS-CoV-2 more effectively than REM at the same concentration. Additionally, pre-treatment of Vero cells with both REM and MMPD in combination reduces the infectious titer of SARS-CoV-2 to values below the detectable limit of our TCID50 assay. This result was achieved with concentrations as small as 1.25 µM MMPD and 2.5 µM REM. At concentrations of each agent as low as 0.31 µM, significant reduction of viral production occurred. This study provides evidence that REM and MMPD administered in combination might be an effective treatment for COVID-19 cases.


2021 ◽  
Author(s):  
Keda Chen ◽  
Feike Ma ◽  
Ying Wang ◽  
Xinyi Zhuang ◽  
Xuning Zhang ◽  
...  

Abstract The novel coronavirus (COVID-19 or 2019-nCoV) is a respiratory virus that can exist in the mouth and saliva of patients and spreads through aerosol dispersion. In the face of such a serious epidemic, the World Health Organization (who) recommends that governments and individuals take necessary infection control measures. The novel coronavirus (severe acute respiratory syndrome coronavirus; SARS-CoV-2) spread rapidly, causing varying degrees of respiratory disease and, in severe cases. SARS-CoV-2 is a respiratory disease that can be transmitted through direct transmission, aerosol transmission, or contact. Therefore, stomatological hospitals and departments have become high-infection-risk environments. Accordingly, oral disinfectants that can effectively inactivate the virus have become a highly active area of research. Hexadecyl pyridinium chloride, povidone-iodine, and other common oral disinfectants are the natural primary choices for stomatological hospitals. Therefore, this study investigated the inhibitory effect of hexadecyl pyridinium chloride on SARS-CoV-2 in vitro. Vero cells infected with SARS-CoV-2 were used to determine the disinfection effect; the CCK-8 method was used to determine cytotoxicity, and viral load was determined by real-time PCR. The results showed that hexadecyl pyridinium chloride has no obvious cytotoxic effect on Vero cells in the concentration range 0.0125–0.05 mg/mL. The in vitro experiments showed that hexadecyl pyridinium chloride significantly inhibits the virus at concentrations of 0.1 mg/mL or above at 2 min of action. Thus, the results provide experimental support for the use of hexadecyl pyridinium chloride in stomatological hospitals.


Author(s):  
Natalya Bukreyeva ◽  
Emily K. Mantlo ◽  
Rachel A. Sattler ◽  
Cheng Huang ◽  
Slobodan Paessler ◽  
...  

AbstractThe ongoing COVID-19 pandemic continues to pose a major public health burden around the world. The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected over one million people worldwide as of April, 2020, and has led to the deaths of nearly 300,000 people. No approved vaccines or treatments in the USA currently exist for COVID-19, so there is an urgent need to develop effective countermeasures. The IMPDH inhibitor merimepodib (MMPD) is an investigational antiviral drug that acts as a noncompetitive inhibitor of IMPDH. It has been demonstrated to suppress replication of a variety of emerging RNA viruses. We report here that MMPD suppresses SARS-CoV-2 replication in vitro. After overnight pretreatment of Vero cells with 10 μM of MMPD, viral titers were reduced by 4 logs of magnitude, while pretreatment for 4 hours resulted in a 3-log drop. The effect is dose-dependent, and concentrations as low as 3.3 μM significantly reduced viral titers when the cells were pretreated prior to infection. The results of this study provide evidence that MMPD may be a viable treatment option for COVID-19.


1997 ◽  
Vol 322 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Namita SEN ◽  
Alan R. SPITZER ◽  
Avinash CHANDER

Synexin (annexin VII) is a member of the annexin family of calcium and phospholipid binding proteins that promote calcium-dependent aggregation and fusion of lipid vesicles or secretory granules. We have previously suggested that synexin may be involved in membrane fusion processes during exocytosis of lung surfactant since it promotes fusion in vitro of lamellar bodies with plasma membranes. In this study, we characterized calcium-dependency of synexin binding to lamellar bodies and plasma membranes, since such binding is the initial, and, therefore, may be the rate-limiting step in membrane aggregation and fusion. The binding of biotinylated synexin to lamellar bodies and plasma membranes increased in a calcium-dependent manner reaching a maximum at approx. 200 ƁM Ca2+. Binding to lamellar bodies was completely inhibited by unlabelled synexin. Gel-overlay analysis showed that synexin bound to an approx. 76 kDa protein in the lamellar body and plasma membrane fractions. The calcium kinetics were noticeably similar for synexin binding to lamellar bodies and plasma membranes, aggregation of lamellar bodies, and fusion of lamellar bodies with lipid vesicles. At low calcium concentrations, aggregation of lamellar bodies could be increased with increasing synexin concentration, and arachidonic acid increased all three parameters (binding, aggregation, and fusion) in a similar manner. The effects of calcium and arachidonic acid on these three parameters suggest that synexin binding to lamellar bodies may be a rate-determining step for fusion during surfactant secretion. Furthermore, at near physiological calcium levels, the membrane fusion may be enhanced by elevated concentrations of synexin and polyunsaturated fatty acids.


2021 ◽  
Author(s):  
Keda Chen ◽  
Feike Ma ◽  
Ying Wang ◽  
Xinyi Zhuang ◽  
Xuning Zhang ◽  
...  

Abstract The novel coronavirus (COVID-19 or 2019-nCoV) is a respiratory virus that can exist in the mouth and saliva of patients and spreads through aerosol dispersion. Therefore, stomatological hospitals and departments have become high-infection-risk environments. Accordingly, the search for oral disinfectants that can effectively inactivate the virus has become a highly active area of research. Hexadecyl pyridinium chloride, povidone-iodine, and other common oral disinfectants are the natural primary choices for stomatological hospitals. Therefore, this study investigated the inhibitory effect of hexadecyl pyridinium chloride on SARS-CoV-2 in vitro. Vero cells infected with SARS-CoV-2 were used to determine disinfection effect; the CCK-8 method was used to determine cytotoxicity; and viral load was determined by real-time PCR. The results showed that hexadecyl pyridinium chloride has no obvious cytotoxic effect on Vero cells in the concentration range 0.0125–0.05 mg/mL. The in vitro experiments showed that hexadecyl pyridinium chloride significantly inhibits the virus at concentrations of 0.1 mg/mL or above at 2 min of action. Thus, the results provide experimental support for the use of hexadecyl pyridinium chloride in stomatological hospitals.


Author(s):  
Lara Bittmann

On December 31, 2019, WHO was informed of cases of pneumonia of unknown cause in Wuhan City, China. A novel coronavirus was identified as the cause by Chinese authorities on January 7, 2020 and was provisionally named "2019-nCoV". This new Coronavirus causes a clinical picture which has received now the name COVID-19. The virus has spread subsequently worldwide and was explained on the 11th of March, 2020 by the World Health Organization to the pandemic.


Author(s):  
Sisir Nandi ◽  
Mohit Kumar ◽  
Mridula Saxena ◽  
Anil Kumar Saxena

Background: The novel coronavirus disease (COVID-19) is caused by a new strain (SARS-CoV-2) erupted in 2019. Nowadays, it is a great threat that claims uncountable lives worldwide. There is no specific chemotherapeutics developed yet to combat COVID-19. Therefore, scientists have been devoted in the quest of the medicine that can cure COVID- 19. Objective: Existing antivirals such as ASC09/ritonavir, lopinavir/ritonavir with or without umifenovir in combination with antimalarial chloroquine or hydroxychloroquine have been repurposed to fight the current coronavirus epidemic. But exact biochemical mechanisms of these drugs towards COVID-19 have not been discovered to date. Method: In-silico molecular docking can predict the mode of binding to sort out the existing chemotherapeutics having a potential affinity towards inhibition of the COVID-19 target. An attempt has been made in the present work to carry out docking analyses of 34 drugs including antivirals and antimalarials to explain explicitly the mode of interactions of these ligands towards the COVID-19protease target. Results: 13 compounds having good binding affinity have been predicted towards protease binding inhibition of COVID-19. Conclusion: Our in silico docking results have been confirmed by current reports from clinical settings through the citation of suitable experimental in vitro data available in the published literature.


Author(s):  
Ekta Shirbhate ◽  
Preeti Patel ◽  
Vijay K Patel ◽  
Ravichandran Veerasamy ◽  
Prabodh C Sharma ◽  
...  

: The novel coronavirus disease-19 (COVID-19), a global pandemic that emerged from Wuhan, China has today travelled all around the world, so far 216 countries or territories with 21,732,472 people infected and 770,866 deaths globally (as per WHO COVID-19 update dated August 18, 2020). Continuous efforts are being made to repurpose the existing drugs and develop vaccines for combating this infection. Despite, to date, no certified antiviral treatment or vaccine prevails. Although, few candidates have displayed their efficacy in in vitro studies and are being repurposed for COVID-19 treatment. This article summarizes synthetic and semi-synthetic compounds displaying potent activity in their clinical experiences or studies against COVID-19 and also focuses on mode of action of drugs being repositioned against COVID-19.


2020 ◽  
Vol 75 (12) ◽  
pp. 3417-3424 ◽  
Author(s):  
Catherine Hodge ◽  
Fiona Marra ◽  
Catia Marzolini ◽  
Alison Boyle ◽  
Sara Gibbons ◽  
...  

Abstract As global health services respond to the coronavirus pandemic, many prescribers are turning to experimental drugs. This review aims to assess the risk of drug–drug interactions in the severely ill COVID-19 patient. Experimental therapies were identified by searching ClinicalTrials.gov for ‘COVID-19’, ‘2019-nCoV’, ‘2019 novel coronavirus’ and ‘SARS-CoV-2’. The last search was performed on 30 June 2020. Herbal medicines, blood-derived products and in vitro studies were excluded. We identified comorbidities by searching PubMed for the MeSH terms ‘COVID-19’, ‘Comorbidity’ and ‘Epidemiological Factors’. Potential drug–drug interactions were evaluated according to known pharmacokinetics, overlapping toxicities and QT risk. Drug–drug interactions were graded GREEN and YELLOW: no clinically significant interaction; AMBER: caution; RED: serious risk. A total of 2378 records were retrieved from ClinicalTrials.gov, which yielded 249 drugs that met inclusion criteria. Thirteen primary compounds were screened against 512 comedications. A full database of these interactions is available at www.covid19-druginteractions.org. Experimental therapies for COVID-19 present a risk of drug–drug interactions, with lopinavir/ritonavir (10% RED, 41% AMBER; mainly a perpetrator of pharmacokinetic interactions but also risk of QT prolongation particularly when given with concomitant drugs that can prolong QT), chloroquine and hydroxychloroquine (both 7% RED and 27% AMBER, victims of some interactions due to metabolic profile but also perpetrators of QT prolongation) posing the greatest risk. With management, these risks can be mitigated. We have published a drug–drug interaction resource to facilitate medication review for the critically ill patient.


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