scholarly journals BRD2 inhibition blocks SARS-CoV-2 infection in vitro by reducing transcription of the host cell receptor ACE2

2021 ◽  
Author(s):  
Ruilin Tian ◽  
Avi J. Samelson ◽  
Veronica V. Rezelj ◽  
Merissa Chen ◽  
Gokul N. Ramadoss ◽  
...  
Keyword(s):  
Host Response ◽  
Cellular Response ◽  
Cell Receptor ◽  
Human Cells ◽  
Lung Epithelial Cells ◽  
Cell Surface Receptor ◽  
Spike Protein ◽  
Interferon Response ◽  
Surface Receptor

AbstractSARS-CoV-2 infection of human cells is initiated by the binding of the viral Spike protein to its cell-surface receptor ACE2. We conducted an unbiased CRISPRi screen to uncover druggable pathways controlling Spike protein binding to human cells. We found that the protein BRD2 is an essential node in the cellular response to SARS-CoV-2 infection. BRD2 is required for ACE2 transcription in human lung epithelial cells and cardiomyocytes, and BRD2 inhibitors currently evaluated in clinical trials potently block endogenous ACE2 expression and SARS-CoV-2 infection of human cells. BRD2 also controls transcription of several other genes induced upon SARS-CoV-2 infection, including the interferon response, which in turn regulates ACE2 levels. It is possible that the previously reported interaction between the viral E protein and BRD2 evolved to manipulate the transcriptional host response during SARS-CoV-2 infection. Together, our results pinpoint BRD2 as a potent and essential regulator of the host response to SARS-CoV-2 infection and highlight the potential of BRD2 as a novel therapeutic target for COVID-19.

scholarly journals A high-throughput screen for TMPRSS2 expression identifies FDA-approved compounds that can limit SARS-CoV-2 entry

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanwen Chen ◽  
Travis B. Lear ◽  
John W. Evankovich ◽  
Mads B. Larsen ◽  
Bo Lin ◽  
...  
Keyword(s):  
Rational Design ◽  
Surface Expression ◽  
In Vitro Models ◽  
Lung Epithelial Cells ◽  
Cell Surface Receptor ◽  
Pharmacokinetic Data ◽  
Drug Induced ◽  
Global Pandemic ◽  
Surface Receptor

AbstractSARS-CoV-2 (2019-nCoV) is the pathogenic coronavirus responsible for the global pandemic of COVID-19 disease. The Spike (S) protein of SARS-CoV-2 attaches to host lung epithelial cells through the cell surface receptor ACE2, a process dependent on host proteases including TMPRSS2. Here, we identify small molecules that reduce surface expression of TMPRSS2 using a library of 2,560 FDA-approved or current clinical trial compounds. We identify homoharringtonine and halofuginone as the most attractive agents, reducing endogenous TMPRSS2 expression at sub-micromolar concentrations. These effects appear to be mediated by a drug-induced alteration in TMPRSS2 protein stability. We further demonstrate that halofuginone modulates TMPRSS2 levels through proteasomal-mediated degradation that involves the E3 ubiquitin ligase component DDB1- and CUL4-associated factor 1 (DCAF1). Finally, cells exposed to homoharringtonine and halofuginone, at concentrations of drug known to be achievable in human plasma, demonstrate marked resistance to SARS-CoV-2 infection in both live and pseudoviral in vitro models. Given the safety and pharmacokinetic data already available for the compounds identified in our screen, these results should help expedite the rational design of human clinical trials designed to combat active COVID-19 infection.

scholarly journals Hydroxyzine inhibits SARS-CoV-2 Spike protein binding to ACE2 in a qualitative in vitro assay

2021 ◽  
Author(s):  
Maria Dolores Rivas ◽  
Jose Maria Rafael Saponi-Cortes ◽  
Jose Zamorano
Keyword(s):  
Public Health Problem ◽  
In Vitro Assay ◽  
Host Cells ◽  
Cell Surface Receptor ◽  
Spike Protein ◽  
Major Public Health Problem ◽  
Receptor Binding Domain ◽  
Vitro Assay ◽  
Surface Receptor

AbstractCOVID-19 currently represents a major public health problem. Multiple efforts are being performed to control this disease. Vaccinations are already in progress. However, no effective treatments have been found so far. The disease is caused by the SARS-CoV-2 coronavirus that through the Spike protein interacts with its cell surface receptor ACE2 to enter into the host cells. Therefore, compounds able to block this interaction may help to stop disease progression. In this study, we have analyzed the effect of compounds reported to interact and modify the activity of ACE2 on the binding of the Spike protein. Among the compounds tested, we found that hydroxyzine could inhibit the binding of the receptor-binding domain of Spike protein to ACE2 in a qualitative in vitro assay. This finding supports the reported clinical data showing the benefits of hydroxyzine on COVID-19 patients, raising the need for further investigation into its effectiveness in the treatment of COVID-19 given its well-characterized medical properties and affordable cost.

scholarly journals In Vitro Effect of Taraxacum officinale Leaf Aqueous Extract on the Interaction between ACE2 Cell Surface Receptor and SARS-CoV-2 Spike Protein D614 and Four Mutants

2021 ◽  
Vol 14 (10) ◽  
pp. 1055
Author(s):  
Hoai Thi Thu Tran ◽  
Michael Gigl ◽  
Nguyen Phan Khoi Le ◽  
Corinna Dawid ◽  
Evelyn Lamy
Keyword(s):  
Immune Escape ◽  
Taraxacum Officinale ◽  
Cell Surface Receptor ◽  
Spike Protein ◽  
Post Exposure Prophylaxis ◽  
Lung Cells ◽  
Surface Receptor ◽  
Exposure Prophylaxis ◽  
Vitro Effect

To date, there have been rapidly spreading new SARS-CoV-2 “variants of concern”. They all contain multiple mutations in the ACE2 receptor recognition site of the spike protein, compared to the original Wuhan sequence, which is of great concern, because of their potential for immune escape. Here we report on the efficacy of common dandelion (Taraxacum officinale) to block protein–protein interaction of SARS-COV-2 spike to the human ACE2 receptor. This could be shown for the wild type and mutant forms (D614G, N501Y, and a mix of K417N, E484K, and N501Y) in human HEK293-hACE2 kidney and A549-hACE2-TMPRSS2 lung cells. High-molecular-weight compounds in the water-based extract account for this effect. Infection of the lung cells using SARS-CoV-2 spike D614 and spike Delta (B.1.617.2) variant pseudotyped lentivirus particles was efficiently prevented by the extract and so was virus-triggered pro-inflammatory interleukin 6 secretion. Modern herbal monographs consider the usage of this medicinal plant as safe. Thus, the in vitro results reported here should encourage further research on the clinical relevance and applicability of the extract as prevention strategy for SARS-CoV-2 infection in terms of a non-invasive, oral post-exposure prophylaxis.

scholarly journals Common dandelion (Taraxacum officinale) efficiently blocks the interaction between ACE2 cell surface receptor and SARS-CoV-2 spike protein D614, mutants D614G, N501Y, K417N and E484K in vitro

2021 ◽  
Author(s):  
Hoai Thi Thu Tran ◽  
Nguyen Phan Khoi Le ◽  
Michael Gigl ◽  
Corinna Dawid ◽  
Evelyn Lamy
Keyword(s):  
Cell Surface ◽  
Taraxacum Officinale ◽  
Cell Surface Receptor ◽  
Spike Protein ◽  
Lung Cells ◽  
Protein Protein Interaction ◽  
Water Based ◽  
Surface Receptor ◽  
Common Dandelion

AbstractOn 11th March 2020, coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, was declared as a global pandemic by the World Health Organization (WHO). To date, there are rapidly spreading new “variants of concern” of SARS-CoV-2, the United Kingdom (B.1.1.7), the South African (B.1.351) or Brasilian (P.1) variant. All of them contain multiple mutations in the ACE2 receptor recognition site of the spike protein, compared to the original Wuhan sequence, which is of great concern, because of their potential for immune escape. Here we report on the efficacy of common dandelion (Taraxacum officinale) to block protein-protein interaction of spike S1 to the human ACE2 cell surface receptor. This could be shown for the original spike D614, but also for its mutant forms (D614G, N501Y, and mix of K417N, E484K, N501Y) in human HEK293-hACE2 kidney and A549-hACE2-TMPRSS2 lung cells. High molecular weight compounds in the water-based extract account for this effect. Infection of the lung cells using SARS-CoV-2 spike pseudotyped lentivirus particles was efficiently prevented by the extract and so was virus-triggered pro-inflammatory interleukin 6 secretion. Modern herbal monographs consider the usage of this medicinal plant as safe. Thus, the in vitro results reported here should encourage further research on the clinical relevance and applicability of the extract as prevention strategy for SARS-CoV-2 infection.Significance statementSARS-CoV-2 is steadily mutating during continuous transmission among humans. This might eventually lead the virus into evading existing therapeutic and prophylactic approaches aimed at the viral spike. We found effective inhibition of protein-protein interaction between the human virus cell entry receptor ACE2 and SARS-CoV-2 spike, including five relevant mutations, by water-based common dandelion (Taraxacum officinale) extracts. This was shown in vitro using human kidney (HEK293) and lung (A549) cells, overexpressing the ACE2 and ACE2/TMPRSS2 protein, respectively. Infection of the lung cells using SARS-CoV-2 pseudotyped lentivirus was efficiently prevented by the extract. The results deserve more in-depth analysis of dandelions’ effectiveness in SARS-CoV-2 prevention and now require confirmatory clinical evidence.

scholarly journals Hapten reactive inducer T cells. II. Evidence that a secreted form of the T cell receptor induces antibody production.

1983 ◽  
Vol 158 (6) ◽  
pp. 1881-1894 ◽  
Author(s):  
R H Dekruyff ◽  
C Clayberger ◽  
H Cantor
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cell Epitope ◽  
Cell Receptor ◽  
Cell Surface Receptor ◽  
Surface Receptor ◽  
In Vitro Response ◽  
Nonspecific Factors

The biologic activity of molecules synthesized and secreted by hapten-specific inducer T cells was examined. After activation, a single inducer clone secretes both antigen-specific inducer peptides as well as nonspecific factors. The nonspecific factors augment the in vitro response of B cells to sheep erythrocytes (SRBC) and Type 2 T-independent antigens. The antigen-specific molecules (ABM) induce plaque-forming cell (PFC) responses in cultures containing ABM, B cells, and antigen that links the epitope recognized by ABM with the B cell epitope. Induction of B cells by ABM is limited to B cells expressing the same I-A allele as the source of the ABM and this reflects binding by ABM to I-A products on B lymphocytes. The data reported here strongly support the view that inducer cells can activate at least some B cells by secretion of a modified form of the T cell surface receptor.

scholarly journals ABD-Derived Protein Blockers of Human IL-17 Receptor A as Non-IgG Alternatives for Modulation of IL-17-Dependent Pro-Inflammatory Axis

2018 ◽  
Vol 19 (10) ◽  
pp. 3089 ◽  
Author(s):  
Marie Hlavničková ◽  
Milan Kuchař ◽  
Radim Osička ◽  
Lucie Vaňková ◽  
Hana Petroková ◽  
...  
Keyword(s):  
Cell Surface ◽  
Clinical Manifestations ◽  
Cell Surface Receptor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Interleukin 17 ◽  
Normal Human Skin ◽  
High Affinity ◽  
Th 17 ◽  
Surface Receptor

Interleukin 17 (IL-17) and its cognate receptor A (IL-17RA) play a crucial role in Th17 cells-mediated pro-inflammatory pathway and pathogenesis of several autoimmune disorders including psoriasis. IL-17 is mainly produced by activated Th-17 helper cells upon stimulation by IL-23 and, via binding to its receptors, mediates IL-17-driven cell signaling in keratinocytes. Hyper-proliferation of keratinocytes belongs to major clinical manifestations in psoriasis. To modulate IL-17-mediated inflammatory cascade, we generated a unique collection of IL-17RA-targeting protein binders that prevent from binding of human IL-17A cytokine to its cell-surface receptor. To this goal, we used a highly complex combinatorial library derived from scaffold of albumin-binding domain (ABD) of streptococcal protein G, and ribosome display selection, to yield a collection of ABD-derived high-affinity ligands of human IL-17RA, called ARS binders. From 67 analyzed ABD variants, 7 different sequence families were identified. Representatives of these groups competed with human IL-17A for binding to recombinant IL-17RA receptor as well as to IL-17RA-Immunoglobulin G chimera, as tested in enzyme-linked immunosorbent assay (ELISA). Five ARS variants bound to IL-17RA-expressing THP-1 cells and blocked binding of human IL-17 cytokine to the cell surface, as tested by flow cytometry. Three variants exhibited high-affinity binding with a nanomolar Kd value to human keratinocyte HaCaT cells, as measured using Ligand Tracer Green Line. Upon IL-17-stimulated activation, ARS variants inhibited secretion of Gro-α (CXCL1) by normal human skin fibroblasts in vitro. Thus, we identified a novel class of inhibitory ligands that might serve as immunosuppressive IL-17RA-targeted non-IgG protein antagonists.

scholarly journals A Targeted Catalytic Nanobody (T-CAN) with Asparaginolytic Activity

Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5637
Author(s):  
Maristella Maggi ◽  
Greta Pessino ◽  
Isabella Guardamagna ◽  
Leonardo Lonati ◽  
Cristina Pulimeno ◽  
...  
Keyword(s):  
Lymphoblastic Leukemia ◽  
Cell Surface Receptor ◽  
Single Domain Antibody ◽  
Antibody Drug Conjugate ◽  
E Coli ◽  
Novel Approach ◽  
Innovative Solutions ◽  
Surface Receptor ◽  
New Type

E. coli L-asparaginase is an amidohydrolase (EC 3.5.1.1) which has been successfully used for the treatment of Acute Lymphoblastic Leukemia for over 50 years. Despite its efficacy, its side effects, and especially its intrinsic immunogenicity, hamper its usage in a significant subset of cases, thus limiting therapeutic options. Innovative solutions to improve on these drawbacks have been attempted, but none of them have been truly successful so far. In this work, we fully replaced the enzyme scaffold, generating an active, miniaturized form of L-asparaginase by protein engineering of a camel single domain antibody, a class of antibodies known to have a limited immunogenicity in humans. We then targeted it onto tumor cells by an antibody scFv fragment directed onto the CD19 B-cell surface receptor expressed on ALL cells. We named this new type of nanobody-based antibody-drug conjugate “Targeted Catalytic Nanobody” (T-CAN). The new molecule retains the catalytic activity and the binding capability of the original modules and successfully targets CD19 expressing cells in vitro. Thanks to its theoretically reduced immunogenic potential compared to the original molecule, the T-CAN can represent a novel approach to tackle current limitations in L-asparaginase usage.

scholarly journals Defective delivery of iron to the developing red cell of the Belgrade laboratory rat

Blood ◽  
1980 ◽  
Vol 55 (4) ◽  
pp. 645-648 ◽  
Author(s):  
JA Edwards ◽  
AL Sullivan ◽  
JE Hoke
Keyword(s):  
B Cells ◽  
Rat Plasma ◽  
Cell Surface Receptor ◽  
Erythroid Cell ◽  
Recessive Trait ◽  
Laboratory Rat ◽  
Surface Receptor ◽  
Normal Rat ◽  
And Control

Erythroid cell iron and transferrin uptake and release was studied in the anemia of the Belgrade laboratory rat (gene symbol, b), an autosomal recessive trait characterized by hypochromia and hyperferrinemia. When reticulocyte-rich red cells were incubated in vitro with doubly (59Fe, 125I) labeled transferrin, b/b cells demonstrated a significantly higher uptake of transferrin (164% of control at 60 min), and a significantly lower uptake of iron (21% of control at 60 min) than control cells. These findings with b/b cells were simulated by sodium-fluoride-treated control cells, but not by trypsin-treated control cells. When reticulocytes exposed to doubly labeled transferrin were incubated in normal rat plasma, there was a substantial loss of 125I from both the b/b cells (mean 71%) and control cells (mean 49%), but only a loss of 59Fe from the b/b cells (mean 21%). These findings suggest a defect in the delivery of iron to the b/b reticulocyte, which is distal to the binding of transferrin to its cell surface receptor.

scholarly journals “Molecular Masks” for ACE2 to Effectively and Safely Block SARS-CoV-2 Virus Entry

2021 ◽  
Vol 22 (16) ◽  
pp. 8963
Author(s):  
Satya Prakash Shukla ◽  
Kwang Bog Cho ◽  
Vineeta Rustagi ◽  
Xiang Gao ◽  
Xinping Fu ◽  
...  
Keyword(s):  
Virus Entry ◽  
Cell Surface Receptor ◽  
Spike Protein ◽  
Pressure Regulation ◽  
Converting Enzyme ◽  
Normal Blood Pressure ◽  
Health Crisis ◽  
Angiotensin Converting Enzyme 2 ◽  
Surface Receptor ◽  
Unique Cell

Coronavirus Disease 2019 (COVID-19) remains a global health crisis, despite the development and success of vaccines in certain countries. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, uses its spike protein to bind to the human cell surface receptor angiotensin-converting enzyme 2 (ACE2), which allows the virus to enter the human body. Using our unique cell screening technology, we identified two ACE2-binding peptoid compounds and developed dimeric derivatives (ACE2P1D1 and ACE2P2D1) that effectively blocked spike protein-ACE2 interaction, resulting in the inhibition of SARS-CoV-2 pseudovirus entry into human cells. ACE2P1D1 and ACE2P2D1 also blocked infection by a D614G mutant pseudovirus. More importantly, these compounds do not decrease ACE2 expression nor its enzyme activity (which is important in normal blood pressure regulation), suggesting safe applicability in humans

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