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1.
Chem Commun (Camb) ; 58(33): 5072-5087, 2022 Apr 21.
Article in English | MEDLINE | ID: covidwho-1751766

ABSTRACT

Understanding biological interactions at a molecular level grants valuable information relevant to improving medical treatments and outcomes. Among the suite of technologies available, Atomic Force Microscopy (AFM) is unique in its ability to quantitatively probe forces and receptor-ligand interactions in real-time. The ability to assess the formation of supramolecular bonds and intermediates in real-time on surfaces and living cells generates important information relevant to understanding biological phenomena. Combining AFM with fluorescence-based techniques allows for an unprecedented level of insight not only concerning the formation and rupture of bonds, but understanding medically relevant interactions at a molecular level. As the ability of AFM to probe cells and more complex models improves, being able to assess binding kinetics, chemical topographies, and garner spectroscopic information will likely become key to developing further improvements in fields such as cancer, nanomaterials, and virology. The rapid response to the COVID-19 crisis, producing information regarding not just receptor affinities, but also strain-dependent efficacy of neutralizing nanobodies, demonstrates just how viable and integral to the pre-clinical development of information AFM techniques are in this era of medicine.


Subject(s)
COVID-19 , Nanostructures , Humans , Kinetics , Ligands , Microscopy, Atomic Force/methods
2.
Int J Mol Sci ; 23(6)2022 Mar 11.
Article in English | MEDLINE | ID: covidwho-1742489

ABSTRACT

The pandemic emergency determined by the spreading worldwide of the SARS-CoV-2 virus has focused the scientific and economic efforts of the pharmaceutical industry and governments on the possibility to fight the virus by genetic immunization. The genetic material must be delivered inside the cells by means of vectors. Due to the risk of adverse or immunogenic reaction or replication connected with the more efficient viral vectors, non-viral vectors are in many cases considered as a preferred strategy for gene delivery into eukaryotic cells. This paper is devoted to the evaluation of the gene delivery ability of new synthesized gemini bis-pyridinium surfactants with six methylene spacers, both hydrogenated and fluorinated, in comparison with compounds with spacers of different lengths, previously studied. Results from MTT proliferation assay, electrophoresis mobility shift assay (EMSA), transient transfection assay tests and atomic force microscopy (AFM) imaging confirm that pyridinium gemini surfactants could be a valuable tool for gene delivery purposes, but their performance is highly dependent on the spacer length and strictly related to their structure in solution. All the fluorinated compounds are unable to transfect RD-4 cells, if used alone, but they are all able to deliver a plasmid carrying an enhanced green fluorescent protein (EGFP) expression cassette, when co-formulated with 1,2-dioleyl-sn-glycero-3-phosphoethanolamine (DOPE) in a 1:2 ratio. The fluorinated compounds with spacers formed by six (FGP6) and eight carbon atoms (FGP8) give rise to a very interesting gene delivery activity, greater to that of the commercial reagent, when formulated with DOPE. The hydrogenated compound GP16_6 is unable to sufficiently compact the DNA, as shown by AFM images.


Subject(s)
DNA/genetics , Gene Transfer Techniques , Methane/chemistry , Pyridinium Compounds/chemistry , Surface-Active Agents/chemistry , Transfection/methods , A549 Cells , Cell Survival , DNA/chemistry , DNA/metabolism , Genetic Therapy/methods , Halogenation , Humans , Hydrogenation , Methane/metabolism , Microscopy, Atomic Force , Molecular Structure , Plasmids/chemistry , Plasmids/genetics , Plasmids/metabolism , Pyridinium Compounds/metabolism , Reproducibility of Results , Surface-Active Agents/metabolism
3.
J Extracell Vesicles ; 10(14): e12170, 2021 12.
Article in English | MEDLINE | ID: covidwho-1555701

ABSTRACT

SARS-CoV-2 spike protein (S) binds to human angiotensin-converting enzyme 2 (hACE2), allowing virus to dock on cell membrane follow by viral entry. Here, we use high-speed atomic force microscopy (HS-AFM) for real-time visualization of S, and its interaction with hACE2 and small extracellular vesicles (sEVs). Results show conformational heterogeneity of S, flexibility of S stalk and receptor-binding domain (RBD), and pH/temperature-induced conformational change of S. S in an S-ACE2 complex appears as an all-RBD up conformation. The complex acquires a distinct topology upon acidification. S and S2 subunit demonstrate different membrane docking mechanisms on sEVs. S-hACE2 interaction facilitates S to dock on sEVs, implying the feasibility of ACE2-expressing sEVs for viral neutralization. In contrary, S2 subunit docks on lipid layer and enters sEV using its fusion peptide, mimicking the viral entry scenario. Altogether, our study provides a platform that is suitable for real-time visualization of various entry inhibitors, neutralizing antibodies, and sEV-based decoy in blocking viral entry. Teaser: Comprehensive observation of SARS-CoV-2 spike and its interaction with receptor ACE2 and sEV-based decoy in real time using HS-AFM.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Extracellular Vesicles/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2/chemistry , Humans , Hydrogen-Ion Concentration , Lipid Bilayers/metabolism , Microscopy, Atomic Force , Protein Binding , Protein Conformation , Protein Domains , Protein Subunits , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Temperature , Virus Internalization
4.
Nat Commun ; 12(1): 6977, 2021 11 30.
Article in English | MEDLINE | ID: covidwho-1545609

ABSTRACT

Despite an unprecedented global gain in knowledge since the emergence of SARS-CoV-2, almost all mechanistic knowledge related to the molecular and cellular details of viral replication, pathology and virulence has been generated using early prototypic isolates of SARS-CoV-2. Here, using atomic force microscopy and molecular dynamics, we investigated how these mutations quantitatively affected the kinetic, thermodynamic and structural properties of RBD-ACE2 complex formation. We observed for several variants of concern a significant increase in the RBD-ACE2 complex stability. While the N501Y and E484Q mutations are particularly important for the greater stability, the N501Y mutation is unlikely to significantly affect antibody neutralization. This work provides unprecedented atomistic detail on the binding of SARS-CoV-2 variants and provides insight into the impact of viral mutations on infection-induced immunity.


Subject(s)
Antibodies, Neutralizing/immunology , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Neutralizing/pharmacology , COVID-19/therapy , COVID-19/virology , Humans , Kinetics , Microscopy, Atomic Force , Molecular Dynamics Simulation , Mutation , Protein Binding/drug effects , Protein Interaction Domains and Motifs , Protein Stability , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Thermodynamics
5.
Int J Mol Sci ; 22(21)2021 Nov 01.
Article in English | MEDLINE | ID: covidwho-1512379

ABSTRACT

The research presented herein follows an urgent global need for the development of novel surface engineering techniques that would allow the fabrication of next-generation cardiovascular stents, which would drastically reduce cardiovascular diseases (CVD). The combination of hydrothermal treatment (HT) and treatment with highly reactive oxygen plasma (P) allowed for the formation of an oxygen-rich nanostructured surface. The morphology, surface roughness, chemical composition and wettability of the newly prepared oxide layer on the Ti substrate were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDX), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle (WCA) analysis. The alteration of surface characteristics influenced the material's bio-performance; platelet aggregation and activation was reduced on surfaces treated by hydrothermal treatment, as well as after plasma treatment. Moreover, it was shown that surfaces treated by both treatment procedures (HT and P) promoted the adhesion and proliferation of vascular endothelial cells, while at the same time inhibiting the adhesion and proliferation of vascular smooth muscle cells. The combination of both techniques presents a novel approach for the fabrication of vascular implants, with superior characteristics.


Subject(s)
Endothelial Cells/cytology , Muscle, Smooth, Vascular/cytology , Plasma/chemistry , Titanium/chemistry , Cell Adhesion , Cell Line , Cell Proliferation , Humans , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Nanostructures , Particle Size , Stents , Surface Properties , Wettability
6.
Langmuir ; 37(41): 12089-12097, 2021 10 19.
Article in English | MEDLINE | ID: covidwho-1450265

ABSTRACT

The COVID-19 pandemic has claimed millions of lives worldwide, sickened many more, and has resulted in severe socioeconomic consequences. As society returns to normal, understanding the spread and persistence of SARS CoV-2 on commonplace surfaces can help to mitigate future outbreaks of coronaviruses and other pathogens. We hypothesize that such an understanding can be aided by studying the binding and interaction of viral proteins with nonbiological surfaces. Here, we propose a methodology for investigating the adhesion of the SARS CoV-2 spike glycoprotein on common inorganic surfaces such as aluminum, copper, iron, silica, and ceria oxides as well as metallic gold. Quantitative adhesion was obtained from the analysis of measured forces at the nanoscale using an atomic force microscope operated under ambient conditions. Without imposing further constraints on the measurement conditions, our preliminary findings suggest that spike glycoproteins interact with similar adhesion forces across the majority of the metal oxides tested with the exception to gold, for which attraction forces ∼10 times stronger than all other materials studied were observed. Ferritin, which was used as a reference protein, was found to exhibit similar adhesion forces as SARS CoV-2 spike protein. This study results show that glycoprotein adhesion forces for similar ambient humidity, tip shape, and contact surface are nonspecific to the properties of metal oxide surfaces, which are expected to be covered by a thin water film. The findings suggest that under ambient conditions, glycoprotein adhesion to metal oxides is primarily controlled by the water capillary forces, and they depend on the surface tension of the liquid water. We discuss further strategies warranted to decipher the intricate nanoscale forces for improved quantification of the adhesion.


Subject(s)
COVID-19 , Humans , Microscopy, Atomic Force , Pandemics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Surface Properties
7.
Biosens Bioelectron ; 195: 113595, 2022 Jan 01.
Article in English | MEDLINE | ID: covidwho-1377664

ABSTRACT

Rapid, mass diagnosis of the coronavirus disease 2019 (COVID-19) is critical to stop the ongoing infection spread. The two standard screening methods to confirm the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are polymerase chain reaction (PCR), through the RNA of the virus, and serology by detecting antibodies produced as a response to the viral infection. However, given the detection complexity, cost and relatively long analysis times of these techniques, novel technologies are urgently needed. Here, we report an aptamer-based biosensor developed on a screen-printed carbon electrode platform for rapid, sensitive, and user-friendly detection of SARS-CoV-2. The aptasensor relies on an aptamer targeting the receptor-binding domain (RBD) in the spike protein (S-protein) of the SARS-CoV-2. The aptamer immobilization on gold nanoparticles, and the presence of S-protein in the aptamer-target complex, investigated for the first time by photo-induced force microscopy mapping between 770 and 1910 cm-1 of the electromagnetic spectrum, revealed abundant S-protein homogeneously distributed on the sensing probe. The detection of SARS-CoV-2 S-protein was achieved by electrochemical impedance spectroscopy after 40 min incubation with several analyte concentrations, yielding a limit of detection of 1.30 pM (66 pg/mL). Moreover, the aptasensor was successfully applied for the detection of a SARS-CoV-2 pseudovirus, thus suggesting it is a promising tool for the diagnosis of COVID-19.


Subject(s)
Biosensing Techniques , COVID-19 , Metal Nanoparticles , Electrodes , Gold , Humans , Microscopy, Atomic Force , SARS-CoV-2
8.
Front Cell Infect Microbiol ; 11: 655501, 2021.
Article in English | MEDLINE | ID: covidwho-1308269

ABSTRACT

Microbes have an arsenal of virulence factors that contribute to their pathogenicity. A number of challenges remain to fully understand disease transmission, fitness landscape, antimicrobial resistance and host heterogeneity. A variety of tools have been used to address diverse aspects of pathogenicity, from molecular host-pathogen interactions to the mechanisms of disease acquisition and transmission. Current gaps in our knowledge include a more direct understanding of host-pathogen interactions, including signaling at interfaces, and direct phenotypic confirmation of pathogenicity. Correlative microscopy has been gaining traction to address the many challenges currently faced in biomedicine, in particular the combination of optical and atomic force microscopy (AFM). AFM, generates high-resolution surface topographical images, and quantifies mechanical properties at the pN scale under physiologically relevant conditions. When combined with optical microscopy, AFM probes pathogen surfaces and their physical and molecular interaction with host cells, while the various modes of optical microscopy view internal cellular responses of the pathogen and host. Here we review the most recent advances in our understanding of pathogens, recent applications of AFM to the field, how correlative AFM-optical microspectroscopy and microscopy have been used to illuminate pathogenicity and how these methods can reach their full potential for studying host-pathogen interactions.


Subject(s)
Host-Pathogen Interactions , Humans , Microscopy, Atomic Force
9.
Sci Rep ; 11(1): 11885, 2021 06 04.
Article in English | MEDLINE | ID: covidwho-1258601

ABSTRACT

SARS-CoV-2 is an enveloped virus responsible for the Coronavirus Disease 2019 (COVID-19) pandemic. Here, single viruses were analyzed by atomic force microscopy (AFM) operating directly in a level 3 biosafety (BSL3) facility, which appeared as a fast and powerful method to assess at the nanoscale level and in 3D infectious virus morphology in its native conformation, or upon inactivation treatments. AFM imaging reveals structurally intact infectious and inactivated SARS-CoV-2 upon low concentration of formaldehyde treatment. This protocol combining AFM and plaque assays allows the preparation of intact inactivated SARS-CoV-2 particles for safe use of samples out of level 3 laboratory to accelerate researches against the COVID-19 pandemic. Overall, we illustrate how adapted BSL3-AFM is a remarkable toolbox for rapid and direct virus analysis based on nanoscale morphology.


Subject(s)
COVID-19/virology , Microscopy, Atomic Force , SARS-CoV-2/ultrastructure , Virion/ultrastructure , Animals , Chlorocebus aethiops , Humans , SARS-CoV-2/physiology , Vero Cells , Virion/physiology , Virus Inactivation
11.
Cells ; 10(3)2021 03 04.
Article in English | MEDLINE | ID: covidwho-1125522

ABSTRACT

Since the outbreak of the COVID-19 crisis, the handling of biological samples from confirmed or suspected SARS-CoV-2-positive individuals demanded the use of inactivation protocols to ensure laboratory operators' safety. While not standardized, these practices can be roughly divided into two categories, namely heat inactivation and solvent-detergent treatments. These routine procedures should also apply to samples intended for Extracellular Vesicles (EVs) analysis. Assessing the impact of virus-inactivating pre-treatments is therefore of pivotal importance, given the well-known variability introduced by different pre-analytical steps on downstream EVs isolation and analysis. Arguably, shared guidelines on inactivation protocols tailored to best address EVs-specific requirements will be needed among the analytical community, yet deep investigations in this direction have not yet been reported. We here provide insights into SARS-CoV-2 inactivation practices to be adopted prior to serum EVs analysis by comparing solvent/detergent treatment vs. heat inactivation. Our analysis entails the evaluation of EVs recovery and purity along with biochemical, biophysical and biomolecular profiling by means of a set of complementary analytical techniques: Nanoparticle Tracking Analysis, Western Blotting, Atomic Force Microscopy, miRNA content (digital droplet PCR) and tetraspanin assessment by microarrays. Our data suggest an increase in ultracentrifugation (UC) recovery following heat treatment; however, it is accompanied by a marked enrichment in EVs-associated contaminants. On the other hand, solvent/detergent treatment is promising for small EVs (<150 nm range), yet a depletion of larger vesicular entities was detected. This work represents a first step towards the identification of optimal serum inactivation protocols targeted to EVs analysis.


Subject(s)
COVID-19/blood , Containment of Biohazards/methods , Extracellular Vesicles/chemistry , Virus Inactivation , COVID-19/virology , Detergents/pharmacology , Extracellular Vesicles/drug effects , Extracellular Vesicles/genetics , Hot Temperature , Humans , MicroRNAs/analysis , Microarray Analysis , Microscopy, Atomic Force , SARS-CoV-2 , Tetraspanins/analysis , Ultracentrifugation
12.
ACS Appl Mater Interfaces ; 13(8): 10321-10327, 2021 Mar 03.
Article in English | MEDLINE | ID: covidwho-1087402

ABSTRACT

Early diagnosis of SARS-CoV-2 infection is critical for facilitating proper containment procedures, and a rapid, sensitive antigen assay is a critical step in curbing the pandemic. In this work, we report the use of a high-purity semiconducting (sc) single-walled carbon nanotube (SWCNT)-based field-effect transistor (FET) decorated with specific binding chemistry to assess the presence of SARS-CoV-2 antigens in clinical nasopharyngeal samples. Our SWCNT FET sensors, with functionalization of the anti-SARS-CoV-2 spike protein antibody (SAb) and anti-nucleocapsid protein antibody, detected the S antigen (SAg) and N antigen (NAg), reaching a limit of detection of 0.55 fg/mL for SAg and 0.016 fg/mL for NAg in calibration samples. SAb-functionalized FET sensors also exhibited good sensing performance in discriminating positive and negative clinical samples, indicating a proof of principle for use as a rapid COVID-19 antigen diagnostic tool with high analytical sensitivity and specificity at low cost.


Subject(s)
Antigens, Viral/analysis , Biosensing Techniques , COVID-19 Testing/instrumentation , Nanotubes, Carbon/chemistry , Semiconductors , Transistors, Electronic , COVID-19 Testing/methods , Calibration , Electrodes , Gold , Humans , Limit of Detection , Materials Testing , Microscopy, Atomic Force , Microscopy, Fluorescence , Nanotechnology , SARS-CoV-2 , Sensitivity and Specificity , Spectrophotometry, Ultraviolet , Spectroscopy, Near-Infrared , Spectrum Analysis, Raman , Spike Glycoprotein, Coronavirus/analysis
13.
Biochem Biophys Res Commun ; 534: 343-346, 2021 01 01.
Article in English | MEDLINE | ID: covidwho-1064871

ABSTRACT

SARS-CoV-2 is a novel coronavirus which has caused the COVID-19 pandemic. Other known coronaviruses show a strong pattern of seasonality, with the infection cases in humans being more prominent in winter. Although several plausible origins of such seasonal variability have been proposed, its mechanism is unclear. SARS-CoV-2 is transmitted via airborne droplets ejected from the upper respiratory tract of the infected individuals. It has been reported that SARS-CoV-2 can remain infectious for hours on surfaces. As such, the stability of viral particles both in liquid droplets as well as dried on surfaces is essential for infectivity. Here we have used atomic force microscopy to examine the structural stability of individual SARS-CoV-2 virus like particles at different temperatures. We demonstrate that even a mild temperature increase, commensurate with what is common for summer warming, leads to dramatic disruption of viral structural stability, especially when the heat is applied in the dry state. This is consistent with other existing non-mechanistic studies of viral infectivity, provides a single particle perspective on viral seasonality, and strengthens the case for a resurgence of COVID-19 in winter.


Subject(s)
COVID-19/transmission , SARS-CoV-2/chemistry , Temperature , COVID-19/epidemiology , COVID-19/virology , Humans , Microscopy, Atomic Force/methods , Pandemics , SARS-CoV-2/physiology , Seasons , Virion/chemistry
14.
Small ; 17(11): e2007091, 2021 03.
Article in English | MEDLINE | ID: covidwho-1060956

ABSTRACT

Search of new strategies for the inhibition of respiratory viruses is one of the urgent health challenges worldwide, as most of the current therapeutic agents and treatments are inefficient. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic and has taken lives of approximately two million people to date. Even though various vaccines are currently under development, virus, and especially its spike glycoprotein can mutate, which highlights a need for a broad-spectrum inhibitor. In this work, inhibition of SARS-CoV-2 by graphene platforms with precise dual sulfate/alkyl functionalities is investigated. A series of graphene derivatives with different lengths of aliphatic chains is synthesized and is investigated for their ability to inhibit SARS-CoV-2 and feline coronavirus. Graphene derivatives with long alkyl chains (>C9) inhibit coronavirus replication by virtue of disrupting viral envelope. The ability of these graphene platforms to rupture viruses is visualized by atomic force microscopy and cryogenic electron microscopy. A large concentration window (10 to 100-fold) where graphene platforms display strongly antiviral activity against native SARS-CoV-2 without significant toxicity against human cells is found. In this concentration range, the synthesized graphene platforms inhibit the infection of enveloped viruses efficiently, opening new therapeutic and metaphylactic avenues against SARS-CoV-2.


Subject(s)
Graphite/chemistry , SARS-CoV-2/chemistry , Antiviral Agents/pharmacology , COVID-19/epidemiology , COVID-19/virology , Cryoelectron Microscopy , Humans , Microscopy, Atomic Force , Pandemics , SARS-CoV-2/drug effects
15.
PLoS Comput Biol ; 16(11): e1008444, 2020 11.
Article in English | MEDLINE | ID: covidwho-1040035

ABSTRACT

We provide a stand-alone software, the BioAFMviewer, which transforms biomolecular structures into the graphical representation corresponding to the outcome of atomic force microscopy (AFM) experiments. The AFM graphics is obtained by performing simulated scanning over the molecular structure encoded in the corresponding PDB file. A versatile molecular viewer integrates the visualization of PDB structures and control over their orientation, while synchronized simulated scanning with variable spatial resolution and tip-shape geometry produces the corresponding AFM graphics. We demonstrate the applicability of the BioAFMviewer by comparing simulated AFM graphics to high-speed AFM observations of proteins. The software can furthermore process molecular movies of conformational motions, e.g. those obtained from servers which model functional transitions within a protein, and produce the corresponding simulated AFM movie. The BioAFMviewer software provides the platform to employ the plethora of structural and dynamical data of proteins in order to help in the interpretation of biomolecular AFM experiments.


Subject(s)
Microscopy, Atomic Force/statistics & numerical data , Software , Computational Biology , Computer Graphics , Computer Simulation , Microscopy, Video/statistics & numerical data , Molecular Dynamics Simulation/statistics & numerical data , Molecular Structure , Motion Pictures , Nanotechnology , Protein Conformation , Proteins/chemistry , Proteins/ultrastructure , User-Computer Interface
16.
Nano Lett ; 21(6): 2675-2680, 2021 03 24.
Article in English | MEDLINE | ID: covidwho-1039625

ABSTRACT

SARS-CoV-2, the virus responsible for the current COVID-19 pandemic, displays a corona-shaped layer of spikes which play a fundamental role in the infection process. Recent structural data suggest that the spikes possess orientational freedom and the ribonucleoproteins segregate into basketlike structures. How these structural features regulate the dynamic and mechanical behavior of the native virion are yet unknown. By imaging and mechanically manipulating individual, native SARS-CoV-2 virions with atomic force microscopy, here, we show that their surface displays a dynamic brush owing to the flexibility and rapid motion of the spikes. The virions are highly compliant and able to recover from drastic mechanical perturbations. Their global structure is remarkably temperature resistant, but the virion surface becomes progressively denuded of spikes upon thermal exposure. The dynamics and the mechanics of SARS-CoV-2 are likely to affect its stability and interactions.


Subject(s)
COVID-19/virology , SARS-CoV-2/chemistry , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/physiology , Virion/chemistry , Virion/physiology , Biomechanical Phenomena , Hot Temperature , Humans , Microscopy, Atomic Force , Models, Molecular , Nanostructures/chemistry , Nanostructures/ultrastructure , Nanotechnology , Pandemics , Protein Conformation , Protein Stability , SARS-CoV-2/ultrastructure , Single Molecule Imaging , Spike Glycoprotein, Coronavirus/ultrastructure , Thermodynamics , Virion/ultrastructure
17.
Int J Mol Sci ; 21(22)2020 Nov 10.
Article in English | MEDLINE | ID: covidwho-917002

ABSTRACT

Pro-inflammatory cytokines like interleukin-1ß (IL-1ß) are upregulated during early responses to tissue damage and are expected to transiently compromise the mechanical microenvironment. Fibroblasts are key regulators of tissue mechanics in the lungs and other organs. However, the effects of IL-1ß on fibroblast mechanics and functions remain unclear. Here we treated human pulmonary fibroblasts from control donors with IL-1ß and used Atomic Force Microscopy to unveil that IL-1ß significantly reduces the stiffness of fibroblasts concomitantly with a downregulation of filamentous actin (F-actin) and alpha-smooth muscle (α-SMA). Likewise, COL1A1 mRNA was reduced, whereas that of collagenases MMP1 and MMP2 were upregulated, favoring a reduction of type-I collagen. These mechanobiology changes were functionally associated with reduced proliferation and enhanced migration upon IL-1ß stimulation, which could facilitate lung repair by drawing fibroblasts to sites of tissue damage. Our observations reveal that IL-1ß may reduce local tissue rigidity by acting both intracellularly and extracellularly through the downregulation of fibroblast contractility and type I collagen deposition, respectively. These IL-1ß-dependent mechanical effects may enhance lung repair further by locally increasing pulmonary tissue compliance to preserve normal lung distension and function. Moreover, our results support that IL-1ß provides innate anti-fibrotic protection that may be relevant during the early stages of lung repair.


Subject(s)
Interleukin-1beta/physiology , Lung/physiology , Actins/metabolism , Adolescent , Adult , Biomechanical Phenomena , Cell Movement/drug effects , Cell Movement/physiology , Cell Proliferation/drug effects , Cell Proliferation/physiology , Cells, Cultured , Collagen Type I/genetics , Collagen Type I/metabolism , Collagen Type III/genetics , Collagen Type III/metabolism , Cyclooxygenase 2/metabolism , Elasticity/drug effects , Elasticity/physiology , Female , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/physiology , Humans , Interleukin-1beta/pharmacology , Lung/cytology , Lung/drug effects , Male , Microscopy, Atomic Force , RNA, Messenger/genetics , RNA, Messenger/metabolism , Regeneration/genetics , Regeneration/physiology , Wound Healing/drug effects , Wound Healing/genetics , Wound Healing/physiology , Young Adult
18.
ACS Appl Mater Interfaces ; 12(52): 58360-58368, 2020 Dec 30.
Article in English | MEDLINE | ID: covidwho-989662

ABSTRACT

The SARS-CoV-2 virus that causes the COVID-19 epidemic can be transmitted via respiratory droplet-contaminated surfaces or fomites, which urgently requires a fundamental understanding of intermolecular interactions of the coronavirus with various surfaces. The corona-like component of the outer surface of the SARS-CoV-2 virion, named spike protein, is a key target for the adsorption and persistence of SARS-CoV-2 on various surfaces. However, a lack of knowledge in intermolecular interactions between spike protein and different substrate surfaces has resulted in ineffective preventive measures and inaccurate information. Herein, we quantified the surface interaction and adhesion energy of SARS-CoV-2 spike protein with a series of inanimate surfaces via atomic force microscopy under a simulated respiratory droplet environment. Among four target surfaces, polystyrene was found to exhibit the strongest adhesion, followed by stainless steel (SS), gold, and glass. The environmental factors (e.g., pH and temperature) played a role in mediating the spike protein binding. According to systematic quantification on a series of inanimate surfaces, the adhesion energy of spike protein was found to be (i) 0-1 mJ/m2 for hydrophilic inorganics (e.g., silica and glass) due to the lack of hydrogen bonding, (ii) 2-9 mJ/m2 for metals (e.g., alumina, SS, and copper) due to the variation of their binding capacity, and (iii) 6-11 mJ/m2 for hydrophobic polymers (e.g., medical masks, safety glass, and nitrile gloves) due to stronger hydrophobic interactions. The quantitative analysis of the nanomechanics of spike proteins will enable a protein-surface model database for SARS-CoV-2 to help generate effective preventive strategies to tackle the epidemic.


Subject(s)
Glass/chemistry , Gold/chemistry , Polystyrenes/chemistry , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Stainless Steel/chemistry , Adsorption , Fomites/virology , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Microscopy, Atomic Force , Surface Properties , Temperature
19.
Proc Natl Acad Sci U S A ; 117(45): 27820-27824, 2020 11 10.
Article in English | MEDLINE | ID: covidwho-889321

ABSTRACT

From the famous 1918 H1N1 influenza to the present COVID-19 pandemic, the need for improved viral detection techniques is all too apparent. The aim of the present paper is to show that identification of individual virus particles in clinical sample materials quickly and reliably is near at hand. First of all, our team has developed techniques for identification of virions based on a modular atomic force microscopy (AFM). Furthermore, femtosecond adaptive spectroscopic techniques with enhanced resolution via coherent anti-Stokes Raman scattering (FASTER CARS) using tip-enhanced techniques markedly improves the sensitivity [M. O. Scully, et al, Proc. Natl. Acad. Sci. U.S.A. 99, 10994-11001 (2002)].


Subject(s)
Microscopy, Atomic Force/methods , SARS-CoV-2/ultrastructure , Spectrum Analysis, Raman/methods , Lasers/standards , Limit of Detection , Microscopy, Atomic Force/instrumentation , Spectrum Analysis, Raman/instrumentation , Time , Virion/ultrastructure
20.
Anal Chem ; 92(16): 11297-11304, 2020 08 18.
Article in English | MEDLINE | ID: covidwho-733551

ABSTRACT

Viruses are infections species that infect a large spectrum of living systems. Although displaying a wide variety of shapes and sizes, they are all composed of nucleic acid encapsulated into a protein capsid. After virions enter the host cell, they replicate to produce multiple copies of themselves. They then lyse the host, releasing virions to infect new cells. The high proliferation rate of viruses is the underlying cause of their fast transmission among living species. Although many viruses are harmless, some of them are responsible for severe diseases such as AIDS, viral hepatitis, and flu. Traditionally, electron microscopy is used to identify and characterize viruses. This approach is time- and labor-consuming, which is problematic upon pandemic proliferation of previously unknown viruses, such as H1N1 and COVID-19. Herein, we demonstrate a novel diagnosis approach for label-free identification and structural characterization of individual viruses that is based on a combination of nanoscale Raman and infrared spectroscopy. Using atomic force microscopy-infrared (AFM-IR) spectroscopy, we were able to probe structural organization of the virions of Herpes Simplex Type 1 viruses and bacteriophage MS2. We also showed that tip-enhanced Raman spectroscopy (TERS) could be used to reveal protein secondary structure and amino acid composition of the virus surface. Our results show that AFM-IR and TERS provide different but complementary information about the structure of complex biological specimens. This structural information can be used for fast and reliable identification of viruses. This nanoscale bimodal imaging approach can be also used to investigate the origin of viral polymorphism and study mechanisms of virion assembly.


Subject(s)
Microscopy, Atomic Force/methods , Nanostructures/chemistry , Spectrum Analysis, Raman/methods , Virion/chemistry , Animals , Betacoronavirus/isolation & purification , Betacoronavirus/physiology , COVID-19 , Capsid/chemistry , Chlorocebus aethiops , Coronavirus Infections/pathology , Coronavirus Infections/virology , Cryoelectron Microscopy , Discriminant Analysis , Herpesvirus 1, Human/physiology , Humans , Influenza A Virus, H1N1 Subtype/physiology , Least-Squares Analysis , Levivirus/metabolism , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Protein Structure, Tertiary , SARS-CoV-2 , Vero Cells
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