Mechanical breathing motions have a fundamental function in lung development and disease, but little is known about how they contribute to host innate immunity. Here we use a human lung alveolus chip ...that experiences cyclic breathing-like deformations to investigate whether physical forces influence innate immune responses to viral infection. Influenza H3N2 infection of mechanically active chips induces a cascade of host responses including increased lung permeability, apoptosis, cell regeneration, cytokines production, and recruitment of circulating immune cells. Comparison with static chips reveals that breathing motions suppress viral replication by activating protective innate immune responses in epithelial and endothelial cells, which are mediated in part through activation of the mechanosensitive ion channel TRPV4 and signaling via receptor for advanced glycation end products (RAGE). RAGE inhibitors suppress cytokines induction, while TRPV4 inhibition attenuates both inflammation and viral burden, in infected chips with breathing motions. Therefore, TRPV4 and RAGE may serve as new targets for therapeutic intervention in patients infected with influenza and other potential pandemic viruses that cause life-threatening lung inflammation.
The conversion of life-threatening viruses into live but avirulent vaccines represents a revolution in vaccinology. In a proof-of-principle study, we expanded the genetic code of the genome of ...influenza A virus via a transgenic cell line containing orthogonal translation machinery. This generated premature termination codon (PTC)-harboring viruses that exerted full infect i vi ty but were replication-incompetent in conventional cells. Genome-wide optimization of the sites for incorporation of multiple PTCs resulted in highly reproductive and genetically stable progeny viruses in transgenic cells. In mouse, ferret, and guinea pig models, vaccination with PTC viruses elicited robust humoral, mucosal, and T cell-mediated immunity against antigenically distinct influenza viruses and even neutralized existing infecting strains. The methods presented here may become a general approach for generating live virus vaccines that can be adapted to almost any virus.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing the coronavirus disease 2019 (COVID-19), has provoked more than six million deaths worldwide and continues to pose a major threat ...to global health. Enormous efforts have been made by researchers around the world to elucidate COVID-19 pathophysiology, design efficacious therapy and develop new vaccines to control the pandemic. To this end, experimental models are essential. While animal models and conventional cell cultures have been widely utilized during these research endeavors, they often do not adequately reflect the human responses to SARS-CoV-2 infection. Therefore, models that emulate with high fidelity the SARS-CoV-2 infection in human organs are needed for discovering new antiviral drugs and vaccines against COVID-19. Three-dimensional (3D) cell cultures, such as lung organoids and bioengineered organs-on-chips, are emerging as crucial tools for research on respiratory diseases. The lung airway, small airway and alveolus organ chips have been successfully used for studies on lung response to infection by various pathogens, including corona and influenza A viruses. In this review, we provide an overview of these new tools and their use in studies on COVID-19 pathogenesis and drug testing. We also discuss the limitations of the existing models and indicate some improvements for their use in research against COVID-19 as well as future emerging epidemics.
Entry inhibitors are of particular importance in current efforts to develop a new generation of anti-influenza virus drugs. Here we report certain pentacyclic triterpenes exhibiting conserved ...structure features and with in vitro anti-influenza virus activity comparable to and even higher than that of oseltamivir. Mechanistic studies indicated that these lead triterpenoids bind tightly to the viral envelope hemagglutinin (HA), disrupting the interaction of HA with the sialic acid receptor and thus the attachment of viruses to host cells. Docking studies suggest that the binding pocket within HA for sialic acid receptor potentially acts as a targeting domain, and this is supported by structure–activity data, sialic acid competition studies, and broad anti-influenza spectrum as well as less induction of drug resistance. Our study might establish the importance of triterpenoids for development of entry inhibitors of influenza viruses.
Multivalent ligands that exhibit high binding affinity to influenza hemagglutinin (HA) trimer can block the interaction of HA with its sialic acid receptor. In this study, a series of multivalent ...pentacyclic triterpene-functionalized per-O-methylated cyclodextrin (CD) derivatives were designed and synthesized using 1, 3-dipolar cycloaddition click reaction. A cell-based assay showed that three compounds (25, 28 and 31) exhibited strong inhibitory activity against influenza A/WSN/33 (H1N1) virus. Compound 28 showed the most potent anti-influenza activity with IC50 of 4.7 μM. The time-of-addition assay indicated that compound 28 inhibited the entry of influenza virus into host cell. Further hemagglutination inhibition (HI) and surface plasmon resonance (SPR) assays indicated that compound 28 tightly bound to influenza HA protein with a dissociation constant (KD) of 4.0 μM. Our results demonstrated a strategy of using per-O-methylated β-CD as a scaffold for designing multivalent compounds to disrupt influenza HA protein-host receptor protein interaction and thus block influenza virus entry into host cells.
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•A total of twelve pentacyclic triterpene/cyclodextrin conjugates were synthesized.•The anti-influenza activities of those multivalent conjugates were evaluated.•Compound 28 displayed the highest anti-influenza activity with an IC50 of 4.7 µM.•Mechanism studies by time-of-addition, HI and SPR assays indicated that the target of compound 28 is HA protein.
The rapid repurposing of antivirals is particularly pressing during pandemics. However, rapid assays for assessing candidate drugs typically involve in vitro screens and cell lines that do not ...recapitulate human physiology at the tissue and organ levels. Here we show that a microfluidic bronchial-airway-on-a-chip lined by highly differentiated human bronchial-airway epithelium and pulmonary endothelium can model viral infection, strain-dependent virulence, cytokine production and the recruitment of circulating immune cells. In airway chips infected with influenza A, the co-administration of nafamostat with oseltamivir doubled the treatment-time window for oseltamivir. In chips infected with pseudotyped severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), clinically relevant doses of the antimalarial drug amodiaquine inhibited infection but clinical doses of hydroxychloroquine and other antiviral drugs that inhibit the entry of pseudotyped SARS-CoV-2 in cell lines under static conditions did not. We also show that amodiaquine showed substantial prophylactic and therapeutic activities in hamsters challenged with native SARS-CoV-2. The human airway-on-a-chip may accelerate the identification of therapeutics and prophylactics with repurposing potential.
Thirteen new oleanane-type triterpenoid saponins, uralsaponins M–Y (1–13), and 15 known analogues (14–28) were isolated from the roots of Glycyrrhiza uralensis Fisch. The structures of 1–13 were ...identified on the basis of extensive NMR and MS data analyses. The sugar residues were identified by gas chromatography and ion chromatography coupled with pulsed amperometric detection after hydrolysis. Saponins containing a galacturonic acid (1–3) or xylose (5) residue are reported from Glycyrrhiza species for the first time. Compounds 1, 7, 8, and 24 exhibited good inhibitory activities against the influenza virus A/WSN/33 (H1N1) in MDCK cells with IC50 values of 48.0, 42.7, 39.6, and 49.1 μM, respectively, versus 45.6 μM of the positive control oseltamivir phosphate. In addition, compounds 24 and 28 showed anti-HIV activities with IC50 values of 29.5 and 41.7 μM, respectively.
Human-to-human transmission of viruses, such as influenza viruses and coronaviruses, can promote virus evolution and the emergence of new strains with increased potential for creating pandemics. ...Clinical studies analyzing how a particular type of virus progressively evolves new traits, such as resistance to antiviral therapies, as a result of passing between different human hosts are difficult to carry out because of the complexity, scale, and cost of the challenge. Here, we demonstrate that spontaneous evolution of influenza A virus through both mutation and gene reassortment can be reconstituted
by sequentially passaging infected mucus droplets between multiple human lung airway-on-a-chip microfluidic culture devices (airway chips). Modeling human-to-human transmission of influenza virus infection on chips in the continued presence of the antiviral drugs amantadine or oseltamivir led to the spontaneous emergence of clinically prevalent resistance mutations, and strains that were resistant to both drugs were identified when they were administered in combination. In contrast, we found that nafamostat, an inhibitor targeting host serine proteases, did not induce viral resistance. This human preclinical model may be useful for studying viral evolution
and identifying potential influenza virus variants before they appear in human populations, thereby enabling preemptive design of new and more effective vaccines and therapeutics.
The rapid evolution of viruses, such as influenza viruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is challenging the use and development of antivirals and vaccines. Studies of within-host viral evolution can contribute to our understanding of the evolutionary and epidemiological factors that shape viral global evolution as well as development of better antivirals and vaccines. However, little is known about how viral evolution of resistance to antivirals occurs clinically due to the lack of preclinical models that can faithfully model influenza infection in humans. Our study shows that influenza viral evolution through mutation or gene reassortment can be recapitulated in a human lung airway-on-a-chip (airway chip) microfluidic culture device that can faithfully recapitulate the influenza infection
This approach is useful for studying within-host viral evolution, evaluating viral drug resistance, and identifying potential influenza virus variants before they appear in human populations, thereby enabling the preemptive design of new and more effective vaccines and therapeutics.
In this study, we aimed to develop a safe and stable form of human growth hormone (hGH) and to refine PEGylation methods for therapeutic proteins via genetic code expansion. Through this precise ...approach, a series of polyethylene glycol (PEG) moieties and sites were combined in various ways. Additionally, the effects of combinatorial PEGylation on the biological, pharmacological, and immunogenic properties of hGH in vitro and vivo were analyzed. Our results showed that combinatorial PEGylation at Y35, G131, and K145 significantly reduced immunogenicity and improved pharmacokinetic (PK) profiles compared with mono-PEGylation, while retaining biological activity. Upon re-examination of the pharmacodynamics in hypophysectomized rats, multi-PEGylated hGH was found to be much more stable than mono-PEGylated hGH. Thus, this method for combinatorial, precise PEGylation may facilitate the development of next-generation, long-acting hGH with low immunogenicity.
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Chemical examination of an arctic actinomycete Streptomyces nitrosporeus resulted in the isolation of two new alkaloids named nitrosporeusines A (1) and B (2), an unprecedented skeleton containing ...benzenecarbothioc cyclopentacpyrrole-1,3-dione. Their structures were determined through extensive spectroscopic analyses in association with X-ray single crystal diffraction. Both 1 and 2 exhibited inhibitory activities against the H1N1 virus in MDCK cells.
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