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1.
Viruses ; 14(12):2786, 2022.
Article in English | MDPI | ID: covidwho-2163623

ABSTRACT

Infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of the COVID-19 pandemic, leads to profound remodeling of cellular membranes, promoting viral replication and virion assembly. A full understanding of this drastic remodeling and the process of virion morphogenesis remains lacking. In this study, we applied room temperature transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) tomography to visualize the SARS-CoV-2 replication factory in Vero cells, and present our results in comparison with published cryo-EM studies. We obtained cryo-EM-like clarity of the ultrastructure by employing high-pressure freezing, freeze substitution (HPF-FS) and embedding, allowing room temperature visualization of double-membrane vesicles (DMVs) in a near-native state. In addition, our data illustrate the consecutive stages of virion morphogenesis and reveal that SARS-CoV-2 ribonucleoprotein assembly and membrane curvature occur simultaneously. Finally, we show the tethering of virions to the plasma membrane in 3D, and that accumulations of virus particles lacking spike protein in large vesicles are most likely not a result of defective virion assembly at their membrane. In conclusion, this study puts forward a room-temperature EM technique providing near-native ultrastructural information about SARS-CoV-2 replication, adding to our understanding of the interaction of this pandemic virus with its host cell.

2.
JACS Au ; 2(9): 2187-2202, 2022 Sep 26.
Article in English | MEDLINE | ID: covidwho-2050266

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 presents a global health emergency. Therapeutic options against SARS-CoV-2 are still very limited but urgently required. Molecular tweezers are supramolecular agents that destabilize the envelope of viruses resulting in a loss of viral infectivity. Here, we show that first-generation tweezers, CLR01 and CLR05, disrupt the SARS-CoV-2 envelope and abrogate viral infectivity. To increase the antiviral activity, a series of 34 advanced molecular tweezers were synthesized by insertion of aliphatic or aromatic ester groups on the phosphate moieties of the parent molecule CLR01. A structure-activity relationship study enabled the identification of tweezers with a markedly enhanced ability to destroy lipid bilayers and to suppress SARS-CoV-2 infection. Selected tweezer derivatives retain activity in airway mucus and inactivate the SARS-CoV-2 wildtype and variants of concern as well as respiratory syncytial, influenza, and measles viruses. Moreover, inhibitory activity of advanced tweezers against respiratory syncytial virus and SARS-CoV-2 was confirmed in mice. Thus, potentiated tweezers are broad-spectrum antiviral agents with great prospects for clinical development to combat highly pathogenic viruses.

3.
Nat Metab ; 3(2): 149-165, 2021 02.
Article in English | MEDLINE | ID: covidwho-1065968

ABSTRACT

Infection-related diabetes can arise as a result of virus-associated ß-cell destruction. Clinical data suggest that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing the coronavirus disease 2019 (COVID-19), impairs glucose homoeostasis, but experimental evidence that SARS-CoV-2 can infect pancreatic tissue has been lacking. In the present study, we show that SARS-CoV-2 infects cells of the human exocrine and endocrine pancreas ex vivo and in vivo. We demonstrate that human ß-cells express viral entry proteins, and SARS-CoV-2 infects and replicates in cultured human islets. Infection is associated with morphological, transcriptional and functional changes, including reduced numbers of insulin-secretory granules in ß-cells and impaired glucose-stimulated insulin secretion. In COVID-19 full-body postmortem examinations, we detected SARS-CoV-2 nucleocapsid protein in pancreatic exocrine cells, and in cells that stain positive for the ß-cell marker NKX6.1 and are in close proximity to the islets of Langerhans in all four patients investigated. Our data identify the human pancreas as a target of SARS-CoV-2 infection and suggest that ß-cell infection could contribute to the metabolic dysregulation observed in patients with COVID-19.


Subject(s)
Islets of Langerhans/virology , SARS-CoV-2/growth & development , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/biosynthesis , Angiotensin-Converting Enzyme 2/genetics , COVID-19/physiopathology , Cells, Cultured , Diabetes Mellitus , Female , Humans , Islets of Langerhans/cytology , Islets of Langerhans/physiopathology , Male , Pancreas, Exocrine/cytology , Pancreas, Exocrine/physiopathology , Pancreas, Exocrine/virology , Pancreatic Diseases/etiology , Pancreatic Diseases/virology , Serine Endopeptidases/biosynthesis , Serine Endopeptidases/genetics , Virus Internalization , Virus Replication
4.
J Am Chem Soc ; 142(40): 17024-17038, 2020 10 07.
Article in English | MEDLINE | ID: covidwho-772998

ABSTRACT

Broad-spectrum antivirals are powerful weapons against dangerous viruses where no specific therapy exists, as in the case of the ongoing SARS-CoV-2 pandemic. We discovered that a lysine- and arginine-specific supramolecular ligand (CLR01) destroys enveloped viruses, including HIV, Ebola, and Zika virus, and remodels amyloid fibrils in semen that promote viral infection. Yet, it is unknown how CLR01 exerts these two distinct therapeutic activities. Here, we delineate a novel mechanism of antiviral activity by studying the activity of tweezer variants: the "phosphate tweezer" CLR01, a "carboxylate tweezer" CLR05, and a "phosphate clip" PC. Lysine complexation inside the tweezer cavity is needed to antagonize amyloidogenesis and is only achieved by CLR01. Importantly, CLR01 and CLR05 but not PC form closed inclusion complexes with lipid head groups of viral membranes, thereby altering lipid orientation and increasing surface tension. This process disrupts viral envelopes and diminishes infectivity but leaves cellular membranes intact. Consequently, CLR01 and CLR05 display broad antiviral activity against all enveloped viruses tested, including herpesviruses, Measles virus, influenza, and SARS-CoV-2. Based on our mechanistic insights, we potentiated the antiviral, membrane-disrupting activity of CLR01 by introducing aliphatic ester arms into each phosphate group to act as lipid anchors that promote membrane targeting. The most potent ester modifications harbored unbranched C4 units, which engendered tweezers that were approximately one order of magnitude more effective than CLR01 and nontoxic. Thus, we establish the mechanistic basis of viral envelope disruption by specific tweezers and establish a new class of potential broad-spectrum antivirals with enhanced activity.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Bridged-Ring Compounds/pharmacology , Organophosphates/pharmacology , Viral Envelope Proteins/drug effects , Acid Phosphatase/chemistry , Acid Phosphatase/metabolism , Amyloid/antagonists & inhibitors , Anti-HIV Agents/chemistry , Anti-HIV Agents/pharmacology , Arginine/chemistry , Betacoronavirus/drug effects , Bridged-Ring Compounds/chemistry , Cell Membrane/chemistry , Cell Membrane/drug effects , Cell Membrane/virology , HIV Infections/drug therapy , HIV-1/drug effects , Humans , Lipids/chemistry , Lysine/chemistry , Magnetic Resonance Spectroscopy , Organophosphates/chemistry , SARS-CoV-2 , Seminal Vesicle Secretory Proteins/chemistry , Seminal Vesicle Secretory Proteins/metabolism , Structure-Activity Relationship , Viral Envelope Proteins/metabolism , Zika Virus/drug effects
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