Peptide Platform as a Powerful Tool in the Fight against COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a global pandemic causing over 195 million infections and more than 4 million fatalities as of July 2021.To date, it has been demonstrated that a number of mutations in the spike glycoprotein (S protein) of SARS-CoV-2 variants of concern abrogate or reduce the neutralization potency of several therapeutic antibodies and vaccine-elicited antibodies. Therefore, the development of additional vaccine platforms with improved supply and logistic profile remains a pressing need. In this work, we have validated the applicability of a peptide-based strategy focused on a preventive as well as a therapeutic purpose. On the basis of the involvement of the dipeptidyl peptidase 4 (DPP4), in addition to the angiotensin converting enzyme 2 (ACE2) receptor in the mechanism of virus entry, we analyzed peptides bearing DPP4 sequences by protein–protein docking and assessed their ability to block pseudovirus infection in vitro. In parallel, we have selected and synthetized peptide sequences located within the highly conserved receptor-binding domain (RBD) of the S protein, and we found that RBD-based vaccines could better promote elicitation of high titers of neutralizing antibodies specific against the regions of interest, as confirmed by immunoinformatic methodologies and in vivo studies. These findings unveil a key antigenic site targeted by broadly neutralizing antibodies and pave the way to the design of pan-coronavirus vaccines.

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In Vitro ACE2 and 5-LOX Enzyme Inhibition by Menthol and Three Different Mint Essential Oils

Natural Product Communications ◽

10.1177/1934578x211055014 ◽

2021 ◽

Vol 16 (11) ◽

pp. 1934578X2110550

Author(s):

Fatih Demirci ◽

Ayşe Esra Karadağ ◽

Sevde Nur Biltekin ◽

Betül Demirci

Keyword(s):

Essential Oils ◽

Enzyme Inhibition ◽

In Vivo Studies ◽

Chemical Compositions ◽

Mentha Arvensis ◽

Angiotensin Converting Enzyme 2 ◽

Potential Applications ◽

Inhibitory Activities

Mentha arvensis L., M. citrata L., and M. spicata L. (family Lamiaceae) essential oils, and their characteristic constituent, menthol, were evaluated in vitro for angiotensin converting enzyme 2 (ACE2) and 5-lipoxygenase (5-LOX) enzyme inhibitory activity. The chemical compositions of M. arvensis, M. citrata, and M. spicata essential oils were analysed both by GC-FID, and GC/MS; 82.0%, 38.1%, and 0.4% menthol were identified, respectively. M. spicata essential oil contained 88.2% carvone as its major component. The enzyme inhibitory activities of the essential oils were evaluated using a fluorometric multiplate based enzyme inhibition kit; the ACE2 inhibitions produced by M. arvensis, M. citrata, and M. spicata essential oils were 33%, 22%, and 73%, while the 5-LOX inhibitions were 84%, 79%, and 70%, respectively. In addition, menthol also showed remarkable ACE2 inhibition of 99.8%, whereas the 5-LOX inhibition was 79.9%. As a result, menthol and the three different mint essential oils may have antiviral potential applications against coronaviruses due to their ACE2 enzyme inhibition and anti-inflammatory features. However, further in vivo studies are needed to confirm the safety and efficacy.

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Robust neutralization assay based on SARS-CoV-2 S-bearing vesicular stomatitis virus (VSV) pseudovirus and ACE2-overexpressed BHK21 cells

10.1101/2020.04.08.026948 ◽

2020 ◽

Cited By ~ 13

Author(s):

Hua-Long Xiong ◽

Yang-Tao Wu ◽

Jia-Li Cao ◽

Ren Yang ◽

Jian Ma ◽

...

Keyword(s):

Vesicular Stomatitis Virus ◽

Neutralizing Antibodies ◽

Neutralization Assay ◽

Cell Number ◽

New Drugs ◽

Human Society ◽

Angiotensin Converting Enzyme 2 ◽

Global Pandemic ◽

Vesicular Stomatitis

AbstractThe global pandemic of Coronavirus disease 2019 (COVID-19) is a disaster for human society. A convenient and reliable in vitro neutralization assay is very important for the development of neutralizing antibodies, vaccines and other inhibitors. In this study, G protein-deficient vesicular stomatitis virus (VSVdG) bearing full-length and truncated spike (S) protein of SARS-CoV-2 were evaluated. The virus packaging efficiency of VSV-SARS-CoV-2-Sdel18 (S with C-terminal 18 amino acid truncation) is much higher than VSV-SARS-CoV-2-S. A neutralization assay for antibody screening and serum neutralizing titer quantification was established based on VSV-SARS-CoV-2-Sdel18 pseudovirus and human angiotensin-converting enzyme 2 (ACE2) overexpressed BHK21 cell (BHK21-hACE2). The experimental results can be obtained by automatically counting EGFP positive cell number at 12 hours after infection, making the assay convenient and high-throughput. The serum neutralizing titer of COVID-19 convalescent patients measured by VSV-SARS-CoV-2-Sdel18 pseudovirus assay has a good correlation with live SARS-CoV-2 assay. Seven neutralizing monoclonal antibodies targeting receptor binding domain (RBD) of SARS-CoV-2-S were obtained. This efficient and reliable pseudovirus assay model could facilitate the development of new drugs and vaccines.

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Identification of a neutralizing epitope within minor repeat region of Plasmodium falciparum CS protein

npj Vaccines ◽

10.1038/s41541-020-00272-6 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

J. Mauricio Calvo-Calle ◽

Robert Mitchell ◽

Rita Altszuler ◽

Caroline Othoro ◽

Elizabeth Nardin

Keyword(s):

Monoclonal Antibodies ◽

Neutralizing Antibodies ◽

In Vivo Studies ◽

Repeat Region ◽

Fine Specificity ◽

Humoral Immune ◽

Major Surface ◽

Murine Monoclonal Antibodies

AbstractMalaria remains a major cause of morbidity and mortality worldwide with 219 million infections and 435,000 deaths predominantly in Africa. The infective Plasmodium sporozoite is the target of a potent humoral immune response that can protect murine, simian and human hosts against challenge by malaria-infected mosquitoes. Early murine studies demonstrated that sporozoites or subunit vaccines based on the sporozoite major surface antigen, the circumsporozoite (CS) protein, elicit antibodies that primarily target the central repeat region of the CS protein. In the current murine studies, using monoclonal antibodies and polyclonal sera obtained following immunization with P. falciparum sporozoites or synthetic repeat peptides, we demonstrate differences in the ability of these antibodies to recognize the major and minor repeats contained in the central repeat region. The biological relevance of these differences in fine specificity was explored using a transgenic P. berghei rodent parasite expressing the P. falciparum CS repeat region. In these in vitro and in vivo studies, we demonstrate that the minor repeat region, comprised of three copies of alternating NANP and NVDP tetramer repeats, contains an epitope recognized by sporozoite-neutralizing antibodies. In contrast, murine monoclonal antibodies specific for the major CS repeats (NANP)n could be isolated from peptide-immunized mice that had limited or no sporozoite-neutralizing activity. These studies highlight the importance of assessing the fine specificity and functions of antirepeat antibodies elicited by P. falciparum CS-based vaccines and suggest that the design of immunogens to increase antibody responses to minor CS repeats may enhance vaccine efficacy.

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Histopathological features of SARS-CoV-2 infection and relationships with organoid technology

Journal of International Medical Research ◽

10.1177/03000605211044382 ◽

2021 ◽

Vol 49 (9) ◽

pp. 030006052110443

Author(s):

İrem İnanç ◽

Esra Erdemli

Keyword(s):

Viral Entry ◽

Three Dimensional ◽

Human Cells ◽

Host Cells ◽

Angiotensin Converting Enzyme 2 ◽

Antiviral Compounds ◽

Global Pandemic ◽

Species Specific

Coronavirus disease 2019 (COVID-19) following infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a global pandemic that is still having serious effects worldwide. This virus, which targets the lungs in particular, can also damage other tissues. Angiotensin converting enzyme 2 (ACE-2) plays a key role in viral entry into host cells. The presence of ACE-2 in various tissues may permit viral infection. Studies of COVID-19 often make use of postmortem tissues. Although this information provides various useful results, it is also necessary to conduct in vitro studies to understand optimal treatment approaches. Because the virus may show species-specific differences, in vitro technologies using human cells are particularly important. Organoid technologies, three-dimensional structures that can be obtained from human cells, are playing increasingly important roles in studies of SARS-CoV-2. This technology offers a significant advantage in terms of mimicking in vivo tissue structures and testing antiviral compounds. In this mini-review, we summarize studies of SARS-CoV-2 using both histopathological and organoid technology approaches.

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In vitro and in vivo preclinical studies predict REGEN-COV protection against emergence of viral escape in humans

10.1101/2021.03.10.434834 ◽

2021 ◽

Author(s):

Richard Copin ◽

Alina Baum ◽

Elzbieta Wloga ◽

Kristen E. Pascal ◽

Stephanie Giordano ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Therapeutic Option ◽

Viral Escape ◽

Spike Protein ◽

In Vivo Studies ◽

Preclinical Studies ◽

Global Pandemic ◽

Emerging Virus

SummaryMonoclonal antibodies against SARS-CoV-2 are a clinically validated therapeutic option against COVID-19. As rapidly emerging virus mutants are becoming the next major concern in the fight against the global pandemic, it is imperative that these therapeutic treatments provide coverage against circulating variants and do not contribute to development of treatment emergent resistance. To this end, we investigated the sequence diversity of the spike protein and monitored emergence of minor virus variants in SARS-COV-2 isolates found in nature or identified from preclinical in vitro and in vivo studies and in the clinic. This study demonstrates that a combination of noncompeting antibodies not only provides full coverage against currently circulating variants but also protects against emergence of new such variants and their potential seeding into the population in a clinical setting.

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A rat monoclonal antibody reacting specifically with the tyrosylated form of alpha-tubulin. I. Biochemical characterization, effects on microtubule polymerization in vitro, and microtubule polymerization and organization in vivo.

The Journal of Cell Biology ◽

10.1083/jcb.97.5.1467 ◽

1983 ◽

Vol 97 (5) ◽

pp. 1467-1475 ◽

Cited By ~ 97

Author(s):

J Wehland ◽

M C Willingham ◽

I V Sandoval

Keyword(s):

Monoclonal Antibody ◽

Biochemical Characterization ◽

Mammalian Species ◽

Antigenic Site ◽

In Vivo Studies ◽

Alpha Tubulin ◽

3T3 Fibroblasts ◽

Microtubule Polymerization

The antigenic site recognized by a rat monoclonal antibody (clone YL 1/2) reacting with alpha-tubulin (Kilmartin, J.V., B. Wright, and C. Milstein, 1982, J. Cell Biol., 93:576-582) has been determined and partially characterized. YL 1/2 reacts specifically with the tyrosylated form of brain alpha-tubulin from different mammalian species. YL 1/2 reacts with the synthetic peptide Gly-(Glu)3-Gly-(Glu)2-Tyr, corresponding to the carboxyterminal amino acid sequence of tyrosylated alpha-tubulin, but does not react with Gly-(Glu)3-Gly-(Glu)2, the constituent peptide of detyrosylated alpha-tubulin. Electron microscopy as well as direct and indirect immunofluorescence microscopy shows that YL 1/2 binds to the surface of microtubules polymerized in vitro and in vivo. Further in vitro studies show that the antibody has no effect on the rate and extent of microtubule polymerization, the stability of microtubules, and the incorporation of the microtubule-associated proteins (MAP2) and tau into microtubules. In vivo studies using Swiss 3T3 fibroblasts injected with YL 1/2 show that; when injected at low concentration (2 mg IgG/ml in the injection solution), the antibody binds to microtubules without changing their distribution in the cytoplasm. Injection of larger concentration of YL 1/2 (6 mg IgG/ml) induces the formation of microtubule bundles, and still higher concentrations cause the aggregation of microtubule bundles around the nucleus (greater than 12 mg IgG/ml).

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Molecular mechanisms linking wound inflammation and fibrosis: knockdown of osteopontin leads to rapid repair and reduced scarring

Journal of Experimental Medicine ◽

10.1084/jem.20071412 ◽

2008 ◽

Vol 205 (1) ◽

pp. 43-51 ◽

Cited By ~ 187

Author(s):

Ryoichi Mori ◽

Tanya J. Shaw ◽

Paul Martin

Keyword(s):

Mast Cell ◽

Neutralizing Antibodies ◽

Molecular Mechanisms ◽

Mouse Skin ◽

Inflammatory Cells ◽

In Vivo Studies ◽

Paracrine Factors ◽

Cultured Fibroblasts

Previous studies of tissue repair have revealed osteopontin (OPN) to be up-regulated in association with the wound inflammatory response. We hypothesize that OPN may contribute to inflammation-associated fibrosis. In a series of in vitro and in vivo studies, we analyze the effects of blocking OPN expression at the wound, and determine which inflammatory cells, and which paracrine factors from these cells, may be responsible for triggering OPN expression in wound fibroblasts. Delivery of OPN antisense oligodeoxynucleotides into mouse skin wounds by release from Pluronic gel decreases OPN protein levels at the wound and results in accelerated healing and reduced granulation tissue formation and scarring. To identify which leukocytic lineages may be responsible for OPN expression, we cultured fibroblasts in macrophage-, neutrophil-, or mast cell–conditioned media (CM), and found that macrophage- and mast cell–secreted factors, specifically platelet-derived growth factor (PDGF), induced fibroblast OPN expression. Correspondingly, Gleevec, which blocks PDGF receptor signaling, and PDGF-Rβ–neutralizing antibodies, inhibited OPN induction by macrophage-CM. These studies indicate that inflammation-triggered expression of OPN both hinders the rate of repair and contributes to wound fibrosis. Thus, OPN and PDGF are potential targets for therapeutic modulation of skin repair to improve healing rate and quality.

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An assessment of the efficacies and therapeutic interventions of homoeopathic medicines in combating viral disorders with implications in the treatment of SARS-CoV-2 (Covid-19), a global pandemic

10.31219/osf.io/tj6dn ◽

2020 ◽

Author(s):

Joy Kumar Dey ◽

Anupam Mukherjee ◽

Sanjay Kumar Dey ◽

Mukut Pratap Udayat ◽

Abhishek Pramanik ◽

...

Keyword(s):

Middle Eastern ◽

Biologically Active ◽

Therapeutic Interventions ◽

In Vivo Studies ◽

The Public ◽

Corona Virus ◽

Global Pandemic ◽

Global Epidemiology

The prevalence of Severe Acute Respiratory Syndrome- Corona Virus-2 (SARS-CoV-2) has undergone a historic transition from December 2019 to April 2020. Under the current circumstances, SARS-CoV-2 has become a key problem for the public health and economic steadiness of the global fraternity. Based on ample of evidence from the global epidemiology of SARS-CoV-2 and MERS-CoV (Middle Eastern Respiratory Syndrome- Corona virus) scientists and physicians strappingly consider these viruses share structural and functional similarities of selected biologically active enzymes namely, 3CLpro, PLpro and RdRp. Ultra-diluted homoeopathic medicine has the legacy to combat infectious as well as viral diseases since last two centuries. Thus, existing antiviral homoeopathic therapies were meta-analysed in the current study and the need of appropriate clinical validation with proper in vitro as well as in vivo studies prior to make clinical endorsements in treating Covid-19 patients with homoeopathic medicines has been explained.

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A bifluorescent-based assay for the identification of neutralizing antibodies against SARS-CoV-2 variants of concern in vitro and in vivo

10.1101/2021.06.28.450214 ◽

2021 ◽

Author(s):

Kevin Chiem ◽

Desarey Morales Vasquez ◽

Jesus Silvas ◽

Jun-Gyu Park ◽

Michael Piepenbrink ◽

...

Keyword(s):

South African ◽

Neutralizing Antibodies ◽

Viral Infections ◽

Rapid Assessment ◽

The United States ◽

Viral Fitness ◽

Angiotensin Converting Enzyme 2 ◽

Protection Efficacy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and has been responsible for the still ongoing coronavirus disease 2019 (COVID-19) pandemic. Prophylactic vaccines have been authorized by the United States (US) Food and Drug Administration (FDA) for the prevention of COVID-19. Identification of SARS-CoV-2 neutralizing antibodies (NAbs) is important to assess vaccine protection efficacy, including their ability to protect against emerging SARS-CoV-2 variants of concern (VoC). Here we report the generation and use of a recombinant (r)SARS-CoV-2 USA/WA1/2020 (WA-1) strain expressing Venus and a rSARS-CoV-2 expressing mCherry and containing mutations K417N, E484K, and N501Y found in the receptor binding domain (RBD) of the spike (S) glycoprotein of the South African (SA) B.1.351 (beta, β) VoC, in bifluorescent-based assays to rapidly and accurately identify human monoclonal antibodies (hMAbs) able to neutralize both viral infections in vitro and in vivo. Importantly, our bifluorescent-based system accurately recapitulated findings observed using individual viruses. Moreover, fluorescent-expressing rSARS-CoV-2 and the parental wild-type (WT) rSARS-CoV-2 WA-1 had similar viral fitness in vitro, as well as similar virulence and pathogenicity in vivo in the K18 human angiotensin converting enzyme 2 (hACE2) transgenic mouse model of SARS-CoV-2 infection. We demonstrate that these new fluorescent-expressing rSARS-CoV-2 can be used in vitro and in vivo to easily identify hMAbs that simultaneously neutralize different SARS-CoV-2 strains, including VoC, for the rapid assessment of vaccine efficacy or the identification of prophylactic and/or therapeutic broadly NAbs for the treatment of SARS-CoV-2 infection.

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Immunoglobulin fragment F(ab’)2 against RBD potently neutralizes SARS-CoV-2 in vitro

10.1101/2020.04.07.029884 ◽

2020 ◽

Cited By ~ 1

Author(s):

Xiaoyan Pan ◽

Pengfei Zhou ◽

Tiejiong Fan ◽

Yan Wu ◽

Jing Zhang ◽

...

Keyword(s):

Neutralizing Antibodies ◽

High Titer ◽

Chinese Hamster Ovary Cells ◽

Chinese Hamster ◽

Inhibitory Effect ◽

Ovary Cells ◽

Global Pandemic ◽

Potent Inhibitory Effect

AbstractCOVID-19 caused by the emerging human coronavirus, SARS-CoV-2, has become a global pandemic, leading a serious threat to human health. So far, there is none vaccines or specific antiviral drugs approved for that. Therapeutic antibodies for SARS-CoV-2, was obtained from hyper immune equine plasma in this study. Herein, SARS-CoV-2 RBD with gram level were obtained through Chinese hamster ovary cells high-density fermentation. The binding of RBD to SARS-CoV-2 receptor, human ACE2, was verified and the efficacy of RBD in vivo was tested on mice and then on horses. As a result, RBD triggered high-titer neutralizing antibodies in vivo, and immunoglobulin fragment F(ab’)2 was prepared from horse antisera through removing Fc. Neutralization test demonstrated that RBD-specific F(ab’)2 inhibited SARS-CoV-2 with EC50 at 0.07 μg/ml, showing a potent inhibitory effect on SARS-CoV-2. These results highlights as RBD-specific F(ab’)2 as therapeutic candidate for SARS-CoV-2.

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