Engineered dityrosine-bonding of the RSV prefusion F protein imparts stability and potency advantages.

Viral fusion proteins facilitate cellular infection by fusing viral and cellular membranes, which involves dramatic transitions from their pre- to postfusion conformations. These proteins are among the most protective viral immunogens, but they are metastable which often makes them intractable as subunit vaccine targets. Adapting a natural enzymatic reaction, we harness the structural rigidity that targeted dityrosine crosslinks impart to covalently stabilize fusion proteins in their native conformations. We show that the prefusion conformation of respiratory syncytial virus fusion protein can be stabilized with two engineered dityrosine crosslinks (DT-preF), markedly improving its stability and shelf-life. Furthermore, it has 11X greater potency as compared with the DS-Cav1 stabilized prefusion F protein in immunogenicity studies and overcomes immunosenescence in mice with simply a high-dose formulation on alum.

Molecular epidemiology and characteristics of respiratory syncytial virus among hospitalized children in Guangzhou, China.

BACKGROUND: Human respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection and hospitalization, especially in children. Highly mutagenic nature and antigenic diversity enable the RSV to successfully survive in human population. We conducted a molecular epidemiological study during 2017-2021 to investigate the prevalence and genetic characteristics of RSV. METHODS: A total of 6499 nasopharyngeal (NP) swabs were collected from hospitalized children at Department of Pediatrics, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong, China. All NP swab specimens were preliminary screened for common respiratory viruses and then tested for RSV using specific PCR assays. Partial G genes of RSV were amplified for phylogenetic analysis and genetic characterization. RESULTS: The overall detection rate for common respiratory viruses was 16.12% (1048/6499). Among those, 405 specimens (6.20%, 405/6499) were found positive for RSV. The monthly distribution of RSV and other respiratory viruses was variable, and the highest incidence was recorded in Autumn and Winter. Based on the sequencing of hypervariable region of G gene, 93 RSV sequences were sub-grouped into RSV-A (56, 60.2%) and RSV-B (37, 39.8%). There was no coinfection of RSV-A and RSV-B in the tested samples. Phylogenetic analysis revealed that RSV-A and RSV-B strains belonged to ON1 and BA9 genotypes respectively, indicating predominance of these genotypes in Guangzhou. Several substitutions were observed which may likely change the antigenicity and pathogenicity of RSV. Multiple glycosylation sites were noticed, demonstrating high selection pressure on these genotypes. CONCLUSION: This study illustrated useful information about epidemiology, genetic characteristics, and circulating genotypes of RSV in Guangzhou China. Regular monitoring of the circulating strains of RSV in different parts of China could assist in the development of more effective vaccines and preventive measures.

Value profile for respiratory syncytial virus vaccines and monoclonal antibodies.

Respiratory syncytial virus (RSV) is the predominant cause of acute lower respiratory infection (ALRI) in young children worldwide, yet no licensed RSV vaccine exists to help prevent the millions of illnesses and hospitalizations and tens of thousands of young lives taken each year. Monoclonal antibody (mAb) prophylaxis exists for prevention of RSV in a small subset of very high-risk infants and young children, but the only currently licensed product is impractical, requiring multiple doses and expensive for the low-income settings where the RSV disease burden is greatest. A robust candidate pipeline exists to one day prevent RSV disease in infant and pediatric populations, and it focuses on two promising passive immunization approaches appropriate for low-income contexts: maternal RSV vaccines and long-acting infant mAbs. Licensure of one or more candidates is feasible over the next one to three years and, depending on final product characteristics, current economic models suggest both approaches are likely to be cost-effective. Strong coordination between maternal and child health programs and the Expanded Program on Immunization will be needed for effective, efficient, and equitable delivery of either intervention. This 'Vaccine Value Profile' (VVP) for RSV is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations, and in collaboration with stakeholders from the WHO headquarters. All contributors have extensive expertise on various elements of the RSV VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Integrating metabolomics and network pharmacology to assess the effects of quercetin on lung inflammatory injury induced by human respiratory syncytial virus.

Quercetin (QR) has significant anti-respiratory syncytial virus (RSV) effects. However, its therapeutic mechanism has not been thoroughly explored. In this study, a lung inflammatory injury model caused by RSV was established in mice. Untargeted lung tissue metabolomics was used to identify differential metabolites and metabolic pathways. Network pharmacology was used to predict potential therapeutic targets of QR and analyze biological functions and pathways modulated by QR. By overlapping the results of the metabolomics and the network pharmacology analyses, the common targets of QR that were likely to be involved in the amelioration of RSV-induced lung inflammatory injury by QR were identified. Metabolomics analysis identified 52 differential metabolites and 244 corresponding targets, while network pharmacology analysis identified 126 potential targets of QR. By intersecting these 244 targets with the 126 targets, hypoxanthine-guanine phosphoribosyltransferase (HPRT1), thymidine phosphorylase (TYMP), lactoperoxidase (LPO), myeloperoxidase (MPO), and cytochrome P450 19A1 (CYP19A1) were identified as the common targets. The key targets, HPRT1, TYMP, LPO, and MPO, were components of purine metabolic pathways. The present study demonstrated that QR effectively ameliorated RSV-induced lung inflammatory injury in the established mouse model. Combining metabolomics and network pharmacology showed that the anti-RSV effect of QR was closely associated with purine metabolism pathways.

Effect of hot water extracts of Arthrospira maxima (spirulina) against respiratory syncytial virus.

BACKGROUND: Spirulina (Arthrospira maxima) hot water extracts such as calcium spirulan (Ca-SP) have demonstrated antiviral effects against herpes simplex virus (HSV), human immunodeficiency virus-1 (HIV-1), and influenza virus infections. There is no prior evidence suggesting the anti-viral activity of the spirulina hot water extract against respiratory syncytial virus (RSV). PURPOSE: There are currently no effective antivirals available to treat RSV infection. Therefore, the development of safe and novel anti-RSV drugs is urgent and necessary. The aim of this work was to demonstrate the anti-RSV activity of spirulina hot water extracts and determine the potential mechanism of action. METHODS: Cytotoxicity and anti-RSV activity of spirulina hot water extracts were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and neutralization assays, respectively. Potential mechanisms and components were assessed using time of addition, attachment, internalization, pull-down assays, and composition analysis. RESULTS: The polysaccharide-enriched high-molecular weight fraction (>100 kDa, SHD1) had a high total sugar content, with rhamnose accounting for approximately 60 mol% of total monosaccharides. The main glycosyl linkages included 3-, 4-, and 2,3-rhamnopyranosyl linkages. All spirulina hot water extracts showed no toxicity toward human epithelial type 2 (HEp-2) cells but demonstrated anti-RSV activity. The SHD1 had a half maximal effective concentration (EC50) of 0.0915 mg/ml and a selective index (SI) of >261.5 against RSV. SHD1 significantly reduced viral yield in a dose-dependent manner during the RSV attachment stage. SHD1 disrupted RSV internalization and inhibited RSV attachment (G) protein binding to heparan sulfate receptors on the host cell surface, thus preventing RSV attachment and entry. CONCLUSION: SHD1 serves as an effective candidate for novel drug development against RSV infection.

An intranasal recombinant NDV-BRSV Fopt vaccine is safe and reduces lesion severity in a colostrum-deprived calf model of RSV infection.

Human respiratory syncytial virus (HRSV) is a major cause of severe lower respiratory tract disease in infants and the elderly, yet no safe, effective vaccine is commercially available. Closely related bovine RSV (BRSV) causes respiratory disease in young calves, with many similar features to those seen in HRSV. We previously showed that a Newcastle disease virus (NDV)-vectored vaccine expressing the F glycoprotein of HRSV reduced viral loads in lungs of mice and cotton rats and protected from HRSV. However, clinical signs and pathogenesis of disease in laboratory animals following HRSV infection differs from that observed in human infants. Thus, we examined whether a similar vaccine would protect neonatal calves from BRSV infection. Codon-optimized rNDV vaccine (rNDV-BRSV Fopt) was constructed and administered to colostrum-deprived calves. The rNDV-BRSV Fopt vaccine was well-tolerated and there was no evidence of vaccine-enhanced disease in the upper airways or lungs of these calves compared to the non-vaccinated calves. We found two intranasal doses reduces severity of gross and microscopic lesions and decreases viral load in the lungs. Furthermore, serum neutralizing antibodies were generated in vaccinated calves. Finally, reduced lung CXC chemokine levels were observed in vaccinated calves after BRSV challenge. In summary, we have shown that rNDV-BRSV Fopt vaccine is safe in colostrum-deprived calves, and is effective in reducing lung lesions, and decreasing viral load in upper respiratory tract and lungs after challenge.

An Unexpected Encounter: Respiratory Syncytial Virus Nonstructural Protein 1 Interacts with Mediator Subunit MED25.

Human respiratory syncytial virus (RSV) is the leading cause of severe acute lower respiratory tract infections in infants worldwide. Nonstructural protein NS1 of RSV modulates the host innate immune response by acting as an antagonist of type I and type III interferon (IFN) production and signaling in multiple ways. Likely, NS1 performs this function by interacting with different host proteins. In order to obtain a comprehensive overview of the NS1 interaction partners, we performed three complementary protein-protein interaction screens, i.e., BioID, MAPPIT, and KISS. To closely mimic a natural infection, the BioID proximity screen was performed using a recombinant RSV in which the NS1 protein is fused to a biotin ligase. Remarkably, MED25, a subunit of the Mediator complex, was identified in all three performed screening methods as a potential NS1-interacting protein. We confirmed the interaction between MED25 and RSV NS1 by coimmunoprecipitation, not only upon overexpression of NS1 but also with endogenous NS1 during RSV infection. We also demonstrate that the replication of RSV can be enhanced in MED25 knockout A549 cells, suggesting a potential antiviral role of MED25 during RSV infection. Mediator subunits function as transcriptional coactivators and are involved in transcriptional regulation of their target genes. Therefore, the interaction between RSV NS1 and cellular MED25 might be beneficial for RSV during infection by affecting host transcription and the host immune response to infection. IMPORTANCE Innate immune responses, including the production of type I and III interferons, play a crucial role in the first line of defense against RSV infection. However, only a poor induction of type I IFNs is observed during RSV infection, suggesting that RSV has evolved mechanisms to prevent type I IFN expression by the infected host cell. A unique RSV protein, NS1, is largely responsible for this effect, probably through interaction with multiple host proteins. A better understanding of the interactions that occur between RSV NS1 and host proteins may help to identify targets for an effective antiviral therapy. We addressed this question by performing three complementary protein-protein interaction screens and identified MED25 as an RSV NS1-interacting protein. We propose a role in innate anti-RSV defense for this Mediator complex subunit.

The titers, duration, and residual clinical protection of passively transferred nasal and serum antibodies are similar among beef calves that nursed colostrum from vaccinated or unvaccinated dams and were challenged experimentally with bovine respiratory syncytial virus at three months of age.

OBJECTIVES: To compare initial titers, duration, and residual clinical protection of passively transferred bovine respiratory syncytial virus (BRSV) nasal immunoglobulin (Ig) G-1 and IgA, and serum neutralizing (SN) antibodies. ANIMALS: 40 three-month-old beef steers born either to unvaccinated or vaccinated cows. PROCEDURES: During the last trimester of gestation, cows were assigned randomly to either vaccinated or unvaccinated groups. Calves were grouped on the basis of whether they nursed colostrum from unvaccinated dams (NO-VACC group; n = 20) versus dams vaccinated with 2 doses of an inactivated BRSV vaccine (VACC group; n = 20). At 3 months of age, calves were challenged with BRSV. Respiratory signs were scored. Nasal BRSV IgG-1 and IgA and SN antibodies were compared before and after the challenge. The presence of BRSV in nasal secretions was evaluated by reverse transcription-PCR assays. RESULTS: Respiratory scores after BRSV challenge were similar between treatment groups. Nasal BRSV IgG-1 and SN antibodies were significantly greater in VACC calves at 48 hours of life; however, by 3 months of age, titers had decayed in both groups. Nasal BRSV IgA titers were minimal after colostrum intake and before the BRSV challenge, and increased in both groups after the challenge. The NO-VACC group had a significantly greater probability of shedding BRSV compared with VACC calves. CLINICAL RELEVANCE: At 3 months of age, titers of passively transferred BRSV antibodies in VACC and NO-VACC calves had decayed to nonprotective levels. Calves born to vaccinated dams had a decreased probability of BRSV shedding; however, this was not related to differences in SN or nasal BRSV antibody titers.

Qingfei oral liquid alleviates RSV-induced lung inflammation by promoting fatty-acid-dependent M1/M2 macrophage polarization via the Akt signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Respiratory syncytial virus (RSV) is a common pathogen that causes lower respiratory tract disease in infants and the elderly, and no vaccination is presently available. Qingfei oral liquid (QF), a traditional Chinese medicine formula, has been shown in clinic to have anti-inflammatory properties. AIM OF THE STUDY: The present study investigated whether QF can suppress RSV-induced lung inflammation in mice models via fatty acid-dependent macrophage polarization. MATERIAL AND METHODS: BALB/c mice were given a low, medium, or high dose of QF intragastrically for four consecutive days following RSV infection. The lung inflammatory status was assessed using H&E staining and cytokine assays. The active components of QF and fatty acid metabolism were analyzed using ultra-high-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). A lipid metabolism-related pathway was found through network pharmacology and molecular docking investigations. Western blotting assays were used to determine the levels of ATP-citrate lyase (ACLY), peroxisome proliferation-activated receptor alpha (PPAR), Akt protein kinase B and its phosphorylated form in Akt signaling. Flow cytometry was used to quantify the number of macrophage subtypes (M1/M2), and immunohistochemistry was used to examine the expression of inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1). RESULTS: In the lung tissues of RSV-infected mice, QF suppressed the transcription of pro-inflammatory proteins such as interleukin-1 beta (IL-1ß), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6), while increasing the level of anti-inflammatory factors such as interleukin-10 (IL-10). The alterations in metabolic enzyme activity mediated by Akt signaling were linked to QF's significant reduction in lung fatty acid accumulation. Lower ACLY expression and higher PPAR expression were found after QF treatment, showing that these two enzymes were downstream targets of Akt signaling, controlling fatty acid synthesis (FAS) and fatty acid oxidation (FAO), respectively. The reprogramming of fatty acid metabolism resulted in the polarization of macrophages from M1 to M2, with lower expression of iNOS and higher expression of Arg-1. Additionally, application of an Akt agonist (SC-79) reduced QF's anti-inflammatory effects by increasing FAS and decreasing macrophage polarization. CONCLUSIONS: QF inhibited Akt-mediated FAS and polarized M1 to M2 macrophages, resulting in an anti-inflammatory impact.

In Utero Ultrafine Particulate Exposure Yields Sex- and Dose-Specific Responses to Neonatal Respiratory Syncytial Virus Infection.

Exposure to particulate matter (PM) is associated with lower respiratory tract infections. The role of ultrafine particles (UFPs, ≤0.1 µm) in respiratory disease is not fully elucidated, especially in models of immunologically immature populations. To characterize the effects of maternal UFP exposure on neonatal infection, we exposed time-mated C57Bl/6n mice to filtered air or UFPs at a low dose (LD, ∼55 µg/m3) and high dose (HD, ∼275 µg/m3) throughout gestation. At 5 days of age, offspring were infected with a respiratory syncytial virus (RSV) strain known to mimic infant infection or sham control. Offspring body weights were significantly reduced in response to infection in the LD RSV group, particularly females. Pulmonary gene expression analysis demonstrated significantly increased levels of oxidative stress- and inflammation-related genes in HD-exposed male offspring in sham and RSV-infected groups. In males, the highest grade of inflammation was observed in the HD RSV group, whereas in females, the LD RSV group showed the most marked inflammation. Overall, findings highlight neonatal responses are dependent on offspring sex and maternal UFP dose. Importantly, infant RSV pathology may be enhanced following even low dose UFP exposure signifying the importance of preventing maternal exposure.

Protein and Peptide Substances in the Treatment of Respiratory Syncytial Infection: Current State.

Respiratory syncytial virus infection (RSVI) is an acute medical and social problem in many countries globally. Infection is most dangerous for infants under one year old and the elderly. Despite its epidemiological relevance, only two drugs are registered for clinical use against RSVI: ribavirin (approved in a limited number of countries due to side effects) and palivizumab (Synagis), which is intended only for the prevention, but not the treatment, of infection. Currently, various research groups are searching for new drugs against RSV, with three main areas of research: small molecules, polymeric drugs (proteins and peptides), and plant extracts. This review is devoted to currently developed protein and peptide anti-RSV drugs.

The effect of Ma-Xin-Gan-Shi decoction on asthma exacerbated by respiratory syncytial virus through regulating TRPV1 channel.

ETHNOPHARMACOLOGICAL RELEVANCE: The incidence and mortality of bronchial asthma are increasing, and respiratory syncytial virus (RSV) is widely regarded as the common cause of clinical exacerbation of asthma. Ma-Xing-Gan-Shi decoction (MXGSD), a classic traditional Chinese medicine prescription, is well-known for treating respiratory diseases, while the mechanism of effecting on RSV-exacerbated asthma remains to be explored. AIM OF THE STUDY: In this study, we investigated the mechanism by which MXGSD exerts a protective effect on asthma exacerbated by RSV in vivo and in vitro. MATERIALS AND METHODS: MXGSD is composed of four Chinese medicine, including Ephedra intermedia Schrenk & C.A.Mey. (herbaceous stem, 27g), Prunus armeniaca L. (dry seed, 27g), Glycyrrhiza uralensis Fisch. (radix and rhizome, 18g), and Gypsum fibrosum (main component: CaSO4·2H2O, 54g). In the present study, the exacerbated asthmatic mice model with the treatment of OVA plus RSV was replicated, and accompanied by the TMT proteomic analysis and further experimental investigations. Then, the protective effect of MXGSD (13.2, 6.6, 3.3 g/kg/d, 7d) on the mice treated by OVA plus RSV, and the mechanism of regulating TRPV1 was explored. In addition, the intracellular Ca2+ concentration of 16HBE cells pretreated with MXGSD medicated serum was also tested after stimulation with the TRPV1 agonist capsaicin. RESULTS: The results suggested that MXGSD could reduce the levels of inflammation cells, airway hyperresponsiveness, and pathological damage of lung tissue. TMT quantitative proteomics analysis and further experimental exploration revealed that MXGSD could reduce the levels of IL-4, IL-13, PGE2, and SP in BAL and down-regulate the expression of TRPV1 mRNA and protein in lung tissue. Furthermore, 16HBE cells stimulated by capsaicin showed an increased intracellular Ca2+ concentration, while the pretreatment of MXGSD medicated serum could reduce it. CONCLUSION: MSGSD showed a protective effect on RSV-exacerbated asthma, which may be related to its regulation of TRPV1 expression and reduction of Th2 cytokines and neurogenic inflammatory mediators. It may provide an objective basis and reference for the clinical application of MXGSD.

Ephedrae Herba and Cinnamomi Cortex interactions with G glycoprotein inhibit respiratory syncytial virus infectivity.

Although respiratory syncytial virus (RSV) is a major cause of respiratory tract infection in children, no effective therapies are available. Recently, RSV G, the attachment glycoprotein, has become a major focus in the development of therapeutic strategies against RSV infection. Treatment of RSV-infected cultured cells with maoto, a traditional herbal medicine for acute febrile diseases, significantly reduced the viral RNA and titers. RSV attachment to the cell surface was inhibited both in the presence of maoto and when RSV particles were pre-treated with maoto. We demonstrated that maoto components, Ephedrae Herba (EH) and Cinnamomi Cortex (CC), specifically interacted with the central conserved domain (CCD) of G protein, and also found that this interaction blocked viral attachment to the cellular receptor CX3CR1. Genetic mutation of CX3C motif on the CCD, the epitope for CX3CR1, decreased the binding capacity to EH and CC, suggesting that CX3C motif was the target for EH and CC. Finally, oral administration of maoto for five days to RSV-infected mice significantly reduced the lung viral titers. These experiments clearly showed the anti-RSV activity of EH and CC mixed in maoto. Taken together, this study provides insights for the rational design of therapies against RSV infection.

Polysaccharides from Platycodonis Radix ameliorated respiratory syncytial virus-induced epithelial cell apoptosis and inflammation through activation of miR-181a-mediated Hippo and SIRT1 pathways.

Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis in young children, but there are few safe and effective treatments for this disease. Platycodonis Radix is widely used as an antitussive and expectorant drug for preventing various diseases in lower respiratory tract, in which the polysaccharides are one of the main bioactivity constituents. In this study, the protective effects of the P. Radix polysaccharides (PRP) against RSV-induced bronchiolitis in juvenile mice and RSV-induced apoptosis of epithelial HEp-2 cells were investigated. The results showed that PRP obviously decreased the levels of IL-1ß, IL-4, IL-6, TNF-α, IFN-γ and TSLP in lung tissues, and reduced the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) of RSV-infected mice. Furthermore, it reduced the apoptosis of RSV-infected HEp-2 cells and remarkably inhibited the mRNA expressions of RSV L gene, which indicated that PRP affected transcription and replication of RSV in host cells. Compared with that in RSV-infected group, miR-181a-5p in the PRP-treated group presented the highest relative abundance and its expression was violently reduced by approximately 30%. Mechanistically, PRP had the similar effects as miR-181a-5p antagomir on RSV-induced apoptosis and inflammation in HEp-2 cells via upregulating BCL2, MLL3 and SIRT1, which could be reversed by miR-181a-5p mimic. Therefore, it demonstrated that PRP not only protected against RSV-induced lung inflammation in mice but also inhibited apoptosis of RSV-infected HEp-2 cells via suppressing miR-181a-5p and transcriptionally activating Hippo and SIRT1 pathways.

Reversible disruption of XPO1-mediated nuclear export inhibits respiratory syncytial virus (RSV) replication.

Respiratory syncytial virus (RSV) is the primary cause of serious lower respiratory tract disease in infants, young children, the elderly and immunocompromised individuals. Therapy for RSV infections is limited to high risk infants and there are no safe and efficacious vaccines. Matrix (M) protein is a major RSV structural protein with a key role in virus assembly. Interestingly, M is localised to the nucleus early in infection and its export into the cytoplasm by the nuclear exporter, exportin-1 (XPO1) is essential for RSV assembly. We have shown previously that chemical inhibition of XPO1 function results in reduced RSV replication. In this study, we have investigated the anti-RSV efficacy of Selective Inhibitor of Nuclear Export (SINE) compounds, KPT-335 and KPT-185. Our data shows that therapeutic administration of the SINE compounds results in reduced RSV titre in human respiratory epithelial cell culture. Within 24 h of treatment, RSV replication and XPO1 expression was reduced, M protein was partially retained in the nucleus, and cell cycle progression was delayed. Notably, the effect of SINE compounds was reversible within 24 h after their removal. Our data show that reversible inhibition of XPO1 can disrupt RSV replication by affecting downstream pathways regulated by the nuclear exporter.

Molecular Mechanism of Jinchan Oral Liquid in the Treatment of Children with Respiratory Syncytial Virus Pneumonia Based on Network Pharmacology and Molecular Docking Technology.

OBJECTIVE: Exploration of the underlying molecular mechanism of Jinchan Oral Liquid (JOL) in treating children with the respiratory syncytial virus (RSV) pneumonia to provide new evidence for the clinical application. METHODS: The active components and target genes of JOL were screened by the TCMSP database. The targets of RSV pneumonia were obtained from the GeneCards, OMIM, DrugBank, and PharmGKB database. Then, we constructed the active component-target network and screened the core genes. The overlaps were screened for PPI network analysis, GO analysis, and KEGG analysis. Finally, result validation was performed by molecular docking. RESULTS: According to the screening criteria of the ADME, 74 active compounds of JOL were obtained; after removing redundant targets, we selected 180 potential targets. By screening the online database, 893 RSV pneumonia-related targets were obtained. A total of 82 overlapping genes were chosen by looking for the intersection. The STRING online database was used to acquire PPI relationships, and 16 core genes were obtained. GO and KEGG analyses showed that the main pathways of JOL in treating RSV pneumonia include TNF signaling pathway and IL17 signaling pathway. The molecular docking results showed that the active compounds of JOL had a good affinity with the core genes. CONCLUSION: In this study, we preliminarily discussed the main active ingredients, related targets, and pathways of JOL and predicted the pharmacodynamic basis and the potential therapeutic mechanisms of RSV pneumonia. In summary, the network pharmacology strategy may be helpful for the discovery of multitarget drugs against complex diseases.

Pollen antigens and atmospheric circulation driven seasonal respiratory viral outbreak and its implication to the Covid-19 pandemic.

The patterns of respiratory virus illness are expressed differently between temperate and tropical climates. Tropical outbreaks often peak in wet seasons. Temperate outbreaks typically peak during the winter. The prevailing causal hypotheses focus on sunlight, temperature and humidity variations. Yet no consistent factors have been identified to sufficiently explain seasonal virus emergence and decline at any latitude. Here we demonstrate close connections among global-scale atmospheric circulations, IgE antibody enhancement through seasonal pollen inhalation, and respiratory virus patterns at any populated latitude, with a focus on the US. Pollens emerge each Spring, and the renewed IgE titers in the population are argued to terminate each winter peak of respiratory illness. Globally circulated airborne viruses are postulated to subsequently deposit across the Southern US during lower zonal geostrophic winds each late Summer. This seasonally refreshed viral load is postulated to trigger a new influenza outbreak, once the existing IgE antibodies diminish to a critical value each Fall. Our study offers a new and consistent explanation for the seasonal diminishment of respiratory viral illnesses in temperate climates, the subdued seasonal signature in the tropics, the annually circulated virus phenotypes, and the northerly migration of influenza across the US every year. Our integrated geospatial and IgE hypothesis provides a new perspective for prediction, mitigation and prevention of the outbreak and spread of seasonal respiratory viruses including Covid-19 pandemic.

[Liquid chromatography-mass spectrometry-based metabolomics study of the efficacy of Chinese medicine asthma-relieving decoction on respiratory syncytial virus infection].

Respiratory syncytial virus (RSV) can cause lower respiratory tract infections, such as bronchiolitis in infants. In China, traditional asthma-relieving medicine has numerous clinical applications in the treatment of RSV infections. However, due to the complexity of the traditional Chinese medicine system, its therapeutic mechanism and main pharmacological components remain unclear. Metabolomics can be used to analyze the efficacy of traditional Chinese medicine to provide modern scientific evidence for such treatments. In this study, an animal model experiment was performed with seven groups of three-week-old rats. The model group and five intervention groups were inoculated nasally with RSV for three consecutive days, and the normal group was treated with the same amount of saline for three consecutive days under the same conditions. In parallel, the five intervention groups were treated separately with the following via intragastric administration for seven consecutive days: asthma-relieving traditional Chinese medicine decoction, its three constituent agents (ascending (xuan) therapy, descending (jiang) therapy, pyretic clearing (qing) therapy), and ribavirin. Both normal group and RSV model group were administered with normal saline via intragastric administration as controls for seven consecutive days. The fundus plasma of rats in each group was collected on day 0, day 3, and day 7. Liquid chromatography-mass spectrometry-based untargeted metabolomics analysis was performed to investigate the changes in the metabolome after RSV infection, the effects of the asthma-relieving decoction on the regulation of metabolites related to RSV infection, and the primary source of efficacy. The detected metabolite ions were corrected using internal standards. Multivariate analysis of ions with an RSD value of less than 30% in quality control (QC) samples was used to construct principal component analysis models to monitor the overall metabolic changes of each group. The results showed that, during RSV infection and treatment, the asthma-relieving decoction and the positive control ribavirin had similar effects on the overall metabolic regulation of RSV-infected rats. Among the three asthma-relieving decoction constituent agents, the ascending (xuan) therapy agents which was composed of ephedra and ginkgo had a closer metabolic regulation effect with asthma-relieving decoction, and might be the main source of pharmacological efficacy. Based on the retention time, m/z value and tandem mass spectra in the database established by our laboratory, a total of 150 metabolites were identified. Paired t-tests were performed using data of the identified metabolites before and after RSV infection in each group, and it was found that 83 metabolite levels significantly changed after RSV infection, indicating that RSV infection could lead to disorders of multiple metabolic pathways in rats. The altered pathways included aminoacyl-tRNA biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis, primary bile acid biosynthesis, phenylalanine metabolism and sphingomyelin metabolism. On the third day, the asthma-relieving decoction had regulatory effects on several metabolites such as bile acids, amino acids, organic acids, lipids, etc. Among the three asthma-relieving decoction constituent agents, the ascending (xuan) therapy agents had more similar effects on the regulation of metabolites with the asthma-relieving decoction. On the other hand, the descending (jiang) therapy agents and pyretic clearing (qing) therapy agents down-regulated the abnormal increase in acylcarnitine caused by the RSV infection. Additionally, both asthma-relieving decoction and its constituent agents could maintain the stability of the immune system and metabolism of the intestinal flora in rats. This study used metabolomics to evaluate the efficacy of an asthma-relieving decoction and demonstrate the metabolites and the corresponding changes after asthma-relieving decoction-based treatment. It provides theoretical support for research on the therapeutic mechanism and active ingredients of asthma-relieving decoction.

Salvia plebeia R. Br. polysaccharides (SPP) against RSV (respiratory syncytial virus) infection: Antiviral effect and mechanisms of action.

OBJECTIVE: To investigate the antiviral effect of Salvia plebeia R. Br. polysaccharides (SPP) against RSV and underlying mechanisms. METHODS: SPP was extracted via alcohol-precipitation method and extract was separated into various fractions using ultrafiltration method. The polysaccharide content was determined using UV-Vis. Antiviral effect of SPP and fractions was measured using MTT method and Reed-Muench method. Sixty Balb/c mice were randomly divided into 6 groups, and received either Ribavirin or SPP. Their body weight and food intake were recorded every day throughout the experiment period. The lung index inhibition ratio and pulmonary virus titer were determined followed by the histological analysis of lungs. Furthermore, time-of-addition and effective stage analysis were carried out to determine the mechanism of action. The TLR-3 and TLR-4 levels in the lungs were determined using qRT-PCR. The levels of IFN-γ, IL-2 and TNF-α in serum were determined using ELISA. RESULTS: The SPP content is 4.396%. SPP has shown a good anti-RSV effect both in vitro (TI = 123.041) and in vivo models. The antiviral activity of fractions with molecular weight ≥ 10,000 is found to possess more potent antiviral activity than other fractions. SPP inhibits the RSV proliferation and reduces the lung lesions induced by RSV. The mechanism of action involves the inhibition of TLR-3 and TLR-4 in lungs, up-regulation of IFN-γ and IL-2, and down-regulation of TNF-α in serum. It is also shown to improve the body's immune function. CONCLUSION: SPP has a potential to treat diseases caused by RSV.

Prodrugs of a 1'-CN-4-Aza-7,9-dideazaadenosine C-Nucleoside Leading to the Discovery of Remdesivir (GS-5734) as a Potent Inhibitor of Respiratory Syncytial Virus with Efficacy in the African Green Monkey Model of RSV.

A discovery program targeting respiratory syncytial virus (RSV) identified C-nucleoside 4 (RSV A2 EC50 = 530 nM) as a phenotypic screening lead targeting the RSV RNA-dependent RNA polymerase (RdRp). Prodrug exploration resulted in the discovery of remdesivir (1, GS-5734) that is >30-fold more potent than 4 against RSV in HEp-2 and NHBE cells. Metabolism studies in vitro confirmed the rapid formation of the active triphosphate metabolite, 1-NTP, and in vivo studies in cynomolgus and African Green monkeys demonstrated a >10-fold higher lung tissue concentration of 1-NTP following molar normalized IV dosing of 1 compared to that of 4. A once daily 10 mg/kg IV administration of 1 in an African Green monkey RSV model demonstrated a >2-log10 reduction in the peak lung viral load. These early data following the discovery of 1 supported its potential as a novel treatment for RSV prior to its development for Ebola and approval for COVID-19 treatment.