Glycomic Analysis Reveals That Sialyltransferase Inhibition Is Involved in the Antiviral Effects of Arbidol.

Due to the high mutation rate of influenza virus and the rapid increase of drug resistance, it is imperative to discover host-targeting antiviral agents with broad-spectrum antiviral activity. Considering the discrepancy between the urgent demand of antiviral drugs during an influenza pandemic and the long-term process of drug discovery and development, it is feasible to explore host-based antiviral agents and strategies from antiviral drugs on the market. In the current study, the antiviral mechanism of arbidol (ARB), a broad-spectrum antiviral drug with potent activity at early stages of viral replication, was investigated from the aspect of hemagglutinin (HA) receptors of host cells. N-glycans that act as the potential binding receptors of HA on 16-human bronchial epithelial (16-HBE) cells were comprehensively profiled for the first time by using an in-depth glycomic approach based on TiO2-PGC chip-Q-TOF MS. Their relative levels upon the treatment of ARB and virus were carefully examined by employing an ultra-high sensitive qualitative method based on Chip LC-QQQ MS, showing that ARB treatment led to significant and extensive decrease of sialic acid (SA)-linked N-glycans (SA receptors), and thereby impaired the virus utilization on SA receptors for rolling and entry. The SA-decreasing effect of ARB was demonstrated to result from its inhibitory effect on sialyltransferases (ST), ST3GAL4 and ST6GAL1 of 16-HBE cells. Silence of STs, natural ST inhibitors, as well as sialidase treatment of 16-HBE cells, resulted in similar potent antiviral activity, whereas ST-inducing agent led to the diminished antiviral effect of ARB. These observations collectively suggesting the involvement of ST inhibition in the antiviral effect of ARB. IMPORTANCE This study revealed, for the first time, that ST inhibition and the resulted destruction of SA receptors of host cells may be an underlying mechanism for the antiviral activity of ARB. ST inhibition has been proposed as a novel host-targeting antiviral approach recently and several compounds are currently under exploration. ARB is the first antiviral drug on the market that was found to possess ST inhibiting function. This will provide crucial evidence for the clinical usages of ARB, such as in combination with neuraminidase (NA) inhibitors to exert optimized antiviral effect, etc. More importantly, as an agent that can inhibit the expression of STs, ARB can serve as a novel lead compound for the discovery and development of host-targeting antiviral drugs.

Effects of Lianhuaqingwen Capsules in adults with mild-to-moderate coronavirus disease 2019: an international, multicenter, double-blind, randomized controlled trial.

BACKGROUND: In a randomized trial, Lianhuaqingwen (LHQW) capsule was effective for accelerating symptom recovery among patients with coronavirus disease 2019 (COVID-19). However, the lack of blinding and limited sample sizes decreased the level of clinical evidence. OBJECTIVES: To evaluate the efficacy and safety of LHQW capsule in adults with mild-to-moderate COVID-19. METHODS: We conducted a double-blind randomized controlled trial in adults with mild-to-moderate COVID-19 (17 sites from China, Thailand, Philippine and Vietnam). Patients received standard-of-care alone or plus LHQW capsules (4 capsules, thrice daily) for 14 days. The primary endpoint was the median time to sustained clinical improvement or resolution of nine major symptoms. RESULTS: The full-analysis set consisted of 410 patients in LHQW capsules and 405 in placebo group. LHQW significantly shortened the primary endpoint in the full-analysis set (4.0 vs. 6.7 days, hazards ratio: 1.63, 95% confidence interval: 1.39-1.90). LHQW capsules shortened the median time to sustained clinical improvement or resolution of stuffy or runny nose (2.8 vs. 3.7 days), sore throat (2.0 vs. 2.6 days), cough (3.2 vs. 4.9 days), feeling hot or feverish (1.0 vs. 1.3 days), low energy or tiredness (1.3 vs. 1.9 days), and myalgia (1.5 vs. 2.0 days). The duration to sustained clinical improvement or resolution of shortness of breath, headache, and chills or shivering did not differ significantly between the two groups. Safety was comparable between the two groups. No serious adverse events were reported. INTERPRETATION: LHQW capsules promote recovery of mild-to-moderate COVID-19 via accelerating symptom resolution and were well tolerated. Trial registration ChiCTR2200056727 .

[Thoughts on path of R&D and registration of innovative traditional Chinese medicine with synchronous transformation of "series prescriptions"].

Since the implementation of drug registration in China, the classification of Chinese medicine has greatly met the needs of public health and effectively guided the transformation, inheritance, and innovation of research achievements on traditional Chinese medicine(TCM). In the past 30 years, the development of new Chinese medicine has followed the registration transformation model of " one prescription for single drug". This model refers to the R&D and registration system of modern drugs, and approximates to the " law-abiding" medication method in TCM clinic, while it rarely reflects the sequential therapy of syndrome differentiation and comprehensive treatment with multiple measures. In 2017, Opinions on Deepening the Reform of Review and Approval System and Encouraging the Innovation of Drugs and Medical Devices released by the General Office of the CPC Central Committee and the General Office of the State Council pointed out that it is necessary to " establish and improve the registration and technical evaluation system in line with the characteristics of Chinese medicine, and handle the relationship between the traditional advantages of Chinese medicine and the requirements of modern drug research". Therefore, based on the development law and characteristics of TCM, clinical thinking should be highlighted in the current technical requirements and registration system of research and development of Chinese medicine. Based on the current situation of registration supervision of Chinese medicine and the modern drug research in China, the present study analyzed limitations and deficiency of " one prescription for single drug" in the research and development of Chinese medicine. Additionally, a new type of " series prescriptions" was proposed, which was consistent with clinical thinking and clinical reality. This study is expected to contribute to the independent innovation and high-quality development of the TCM industry.

Comparison of outcomes between neoadjuvant imatinib and upfront surgery in patients with localized rectal GIST: An inverse probability of treatment weighting analysis.

BACKGROUND AND OBJECTIVES: This study aimed to compare outcomes between neoadjuvant imatinib and upfront surgery in patients with localized rectal gastrointestinal stromal tumors (GIST) patients. METHODS: Eighty-five patients with localized rectal GIST were divided into two groups: upfront surgery ± adjuvant imatinib (Group A, n = 33) and the neoadjuvant imatinib + surgery + adjuvant imatinib (Group B, n = 52). Baseline characteristics between groups were controlled for with inverse probability of treatment weighting (IPTW) adjusted analysis. RESULTS: The response rate to neoadjuvant imatinib was 65.9%. After the IPTW-adjusted analysis, patients who underwent neoadjuvant therapy had better distant recurrence-free survival (DRFS) and disease-specific survival (DSS) compared with those who underwent upfront surgery (5-year DRFS 97.8 vs. 71.9%, hazard ratio [HR], 0.15; 95% CI, 0.03-0.87; p = 0.03; 5-year DSS 100 vs. 77.1%; HR, 0.11; 95% CI, 0.01-0.92; p = 0.04). While no significant association was found between overall survival (OS) and treatment groups (p = 0.07), 5-year OS was higher for the neoadjuvant group than upfront surgery group (97.8% vs. 71.9%; HR, 0.2; 95% CI, 0.03-1.15). CONCLUSIONS: In patients with localized rectal GIST, neoadjuvant imatinib not only shrunk the tumor size but also decreased the risk of metastasis and tumor-related deaths when compared to upfront surgery and adjuvant imatinib alone.

Comprehensive Glycomic Profiling of Respiratory Tract Tissues of Tree Shrews by TiO2-PGC Chip Mass Spectrometry.

Due to its relatively small size, homology to humans, and susceptibility to human viruses, the tree shrew becomes an ideal alternative animal model for the study of human viral infectious diseases. However, there is still no report for the comprehensive glycan profile of the respiratory tract tissues in tree shrews. In this study, we characterized the structural diversity of N-glycans in the respiratory tract of tree shrews using our well-established TiO2-PGC chip-Q-TOF-MS method. As a result, a total of 219 N-glycans were identified. Moreover, each identified N-glycan was quantitated by a high sensitivity and accurate MRM method, in which 13C-labeled internal standards were used to correct the inherent run-to-run variation in MS detection. Our results showed that the N-glycan composition in the turbinate and lung was significantly different from the soft palate, trachea, and bronchus. Meanwhile, 28 high-level N-glycans in turbinate were speculated to be correlated with the infection of H1N1 virus A/California/04/2009. This study is the first to reveal the comprehensive glycomic profile of the respiratory tract of tree shrews. Our results also help to better understand the role of glycan receptors in human influenza infection and pathogenesis.

ß-sitosterol ameliorates influenza A virus-induced proinflammatory response and acute lung injury in mice by disrupting the cross-talk between RIG-I and IFN/STAT signaling.

ß-Sitosterol (24-ethyl-5-cholestene-3-ol) is a common phytosterol Chinese medical plants that has been shown to possess antioxidant and anti-inflammatory activity. In this study we investigated the effects of ß-sitosterol on influenza virus-induced inflammation and acute lung injury and the molecular mechanisms. We demonstrate that ß-sitosterol (150-450 µg/mL) dose-dependently suppresses inflammatory response through NF-κB and p38 mitogen-activated protein kinase (MAPK) signaling in influenza A virus (IAV)-infected cells, which was accompanied by decreased induction of interferons (IFNs) (including Type I and III IFN). Furthermore, we revealed that the anti-inflammatory effect of ß-sitosterol resulted from its inhibitory effect on retinoic acid-inducible gene I (RIG-I) signaling, led to decreased STAT1 signaling, thus affecting the transcriptional activity of ISGF3 (interferon-stimulated gene factor 3) complexes and resulting in abrogation of the IAV-induced proinflammatory amplification effect in IFN-sensitized cells. Moreover, ß-sitosterol treatment attenuated RIG-I-mediated apoptotic injury of alveolar epithelial cells (AEC) via downregulation of pro-apoptotic factors. In a mouse model of influenza, pre-administration of ß-sitosterol (50, 200 mg·kg-1·d-1, i.g., for 2 days) dose-dependently ameliorated IAV-mediated recruitment of pathogenic cytotoxic T cells and immune dysregulation. In addition, pre-administration of ß-sitosterol protected mice from lethal IAV infection. Our data suggest that ß-sitosterol blocks the immune response mediated by RIG-I signaling and deleterious IFN production, providing a potential benefit for the treatment of influenza.

Efficacy of indoor air purification in the treatment of Artemisia pollen-allergic rhinitis: A randomised, double-blind, clinical controlled trial.

OBJECTIVES: To evaluate the clinical efficacy of a high-efficiency air purifier in patients with allergic rhinitis. DESIGN: We conducted a randomised, double-blind, clinical controlled trial with active and inactive versions of an air purifier. Our study included patients with allergic rhinitis who were sensitive to Artemisia pollen and treatment of the indoor environment using air filtration at night. We evaluated the clinical efficacy of indoor air filtration during the Artemisia pollen scattering season in Yulin City in Shanxi Province, China. SETTING: The First Hospital of Yulin (Yulin City, Shanxi Province, China). PARTICIPANTS: A total of 90 patients with allergic rhinitis who were sensitive to allergens of Artemisia pollen were randomly assigned to one of two groups in equal numbers. MAIN OUTCOME MEASURES: The primary outcome measure was the difference in visual analogue scale scores from baseline. Secondary outcomes were changes from baseline in nasal symptoms, allergy symptom scores, responses to the Rhinoconjunctivitis Quality of Life Questionnaire, Epworth Sleepiness Scale scores and tolerability scores for the air purifier. RESULTS: Based on the allergy symptom score, we found significant differences in rhinitis symptoms between the groups who used the active versus the inactive air purifier. CONCLUSIONS: The results of our investigation demonstrated the health benefits of particle filtration.

Risk Assessment of the Tropism and Pathogenesis of the Highly Pathogenic Avian Influenza A/H7N9 Virus Using Ex Vivo and In Vitro Cultures of Human Respiratory Tract.

BACKGROUND: Highly pathogenic avian influenza (HPAI)-H7N9 virus arising from low pathogenic avian influenza (LPAI)-H7N9 virus with polybasic amino acid substitutions in the hemagglutinin was detected in 2017. METHODS: We compared the tropism, replication competence, and cytokine induction of HPAI-H7N9, LPAI-H7N9, and HPAI-H5N1 in ex vivo human respiratory tract explants, in vitro culture of human alveolar epithelial cells (AECs) and pulmonary microvascular endothelial cells (HMVEC-L). RESULTS: Replication competence of HPAI- and LPAI-H7N9 were comparable in ex vivo cultures of bronchus and lung. HPAI-H7N9 predominantly infected AECs, whereas limited infection was observed in bronchus. The reduced tropism of HPAI-H7N9 in bronchial epithelium may explain the lack of human-to-human transmission despite a number of mammalian adaptation markers. Apical and basolateral release of virus was observed only in HPAI-H7N9- and H5N1-infected AECs regardless of infection route. HPAI-H7N9, but not LPAI-H7N9 efficiently replicated in HMVEC-L. CONCLUSIONS: Our findings demonstrate that a HPAI-H7N9 virus efficiently replicating in ex vivo cultures of human bronchus and lung. The HPAI-H7N9 was more efficient at replicating in human AECs and HMVEC-L than LPAI-H7N9 implying that endothelial tropism may involve in pathogenesis of HPAI-H7N9 disease.

Analysis of influenza B virus lineages and the HA1 domain of its hemagglutinin gene in Guangzhou, southern China, during 2016.

BACKGROUND: Few studies have analyzed influenza B virus lineages based on hemagglutinin A (HA) gene sequences in southern China. The present study analyzed the HA gene and the lineages of influenza B virus isolates from Guangzhou during 2016, and compared our results with the WHO-recommended vaccine strain. METHODS: Ninety patients with influenza B were recruited from the First Hospital of Guangzhou Medical University. Throat swab specimens of 72 patients had high viral loads. Among these 72 isolates, the HA1 domain of the HA gene in 43 randomly selected isolates was sequenced using reverse transcription-polymerase chain reaction (RT-PCR), and analyzed using MEGA 5.05. RESULTS: Eight of the 90 patients (8.9%) also had influenza A virus infections. Analysis of the 43 influenza B virus isolates indicated that 34 (79.1%) were from the Victoria lineage and 9 (20.9%) were from the Yamagata lineage. A comparison isolates in our Victoria lineage with the B/Brisbane/60/2008 strain indicated 12 mutation sites in the HA1 domain, 4 of which (I132V, N144D, C196S, and E198D) were in antigenic epitopes. A comparison of isolates in our Yamagata lineage with the B/Phuket/3073/2013 stain indicated 5 mutation sites in the HA1 domain, none of which was in an antigenic epitope. None of the isolates had a mutation in regions of the neuraminidase gene (NA) that are known to confer resistance to NA inhibitors. CONCLUSION: In Guangzhou during 2016, most influenza B virus isolates were from the Victoria lineage, in contrast to the vaccine strain recommended by the WHO for this period.

Unprecedented sugar bridged bisindoles selective inhibiting glioma stem cells.

Unlike reported bisindoles linked by single bond directly, alstoniasidines A (1) and B (2), from Alstonia scholaris featuring unprecedented skeleton with two indole moieties bridged by a sugar, represented a novel bisindole type having strictosamide-glucopyranose-picraline scaffold. Both compounds exhibited selective cytotoxicity against human glioma stem cells (GSCs) and induced caspase-3 dependent extrinsic apoptosis by increasing the expression of interleukin 1 (IL-1), tumor necrosis factor (TNF-α), and the cleaved caspase-3, while damaged the unlimited proliferation and self-renewal capacity of GSCs. This finding might provide new type of leads for the selective killing of human glioma stem cells.

Role of viral bioaerosols in nosocomial infections and measures for prevention and control.

The presence of patients with diverse pathologies in hospitals results in an environment that can be rich in various microorganisms including respiratory and enteric viruses, leading to outbreaks in hospitals or spillover infections to the community. All hospital patients are at risk of nosocomial viral infections, but vulnerable groups such as older adults, children and immuno-compromised/-suppressed patients are at particular risk of severe outcomes including prolonged hospitalization or death. These pathogens could transmit through direct or indirect physical contact, droplets or aerosols, with increasing evidence suggesting the importance of aerosol transmission in nosocomial infections of respiratory and enteric viruses. Factors affecting the propensity to transmit and the severity of disease transmitted via the aerosol route include the biological characteristics affecting infectivity of the viruses and susceptibility of the host, the physical properties of aerosol particles, and the environmental stresses that alter these properties such as temperature and humidity. Non-specific systematic and individual-based interventions designed to mitigate the aerosol route are available although empirical evidence of their effectiveness in controlling transmission of respiratory and enteric viruses in healthcare settings are sparse. The relative importance of aerosol transmission in healthcare setting is still an on-going debate, with particular challenge being the recovery of infectious viral bioaerosols from real-life settings and the difficulty in delineating transmission events that may also be a result of other modes of transmission. For the prevention and control of nosocomial infections via the aerosol route, more research is needed on identifying settings, medical procedures or equipment that may be associated with an increased risk of aerosol transmission, including defining which procedures are aerosol-generating; and on the effectiveness of systematic interventions on aerosol transmission of respiratory and enteric viruses in healthcare settings.

Efficacy of indoor air purification in treating Artemisia (mugwort) pollen allergic rhinitis: study protocol for a randomised controlled trial.

BACKGROUND: Allergic rhinitis (AR) is a worldwide health problem. Allergen avoidance is strongly recommended for AR patients. Air purification can reduce concentrations of particles in indoor air, including those of allergens. Air purifiers have been recommended by clinicians for AR patients, but few studies have focused on the removal of airborne allergens from home environments. Such studies have been limited by a lack of blinding, small samples, or a failure to measure allergen levels, disease activity, or a combination of these factors. This study investigates the efficacy of a high-efficiency air purifier in reducing disease activity in the homes of AR patients sensitive to the allergens produced by Artemisia (mugwort) pollen. METHODS: This is a randomized, double-blind, clinical controlled trial that will test active and inactive versions of an air purifier (Atmosphere®; Amway China). Sixty AR patients sensitive to the allergens produced by Artemisia pollen will be assigned randomly to two groups of equal numbers. All patients will undergo a 4-week treatment period and a 4-week observation period. Evaluation will be conducted at baseline (day 0) and on days 7, 14, 21, 28, and 56. The primary outcome measure will be the difference in visual analog scale scores from baseline. Secondary outcomes will be changes from baseline in nasal symptoms, allergy symptom scores, responses to the Rhinoconjunctivitis Quality of Life Questionnaire, Epworth Sleepiness Scale scores, and tolerability scores for the air purifier. Side effects of treatment will be recorded. DISCUSSION: Reducing exposure to allergens can reduce the risk of conditions such as AR. We hypothesise that AR patients sensitive to the allergens produced by Artemisia pollen will not suffer symptoms in a pollen-free environment. AR patients can remove pollen from their homes using air purifiers, decreasing the risk of symptoms. We expect that our study results will provide reliable evidence for determining the effects of air-purification therapy. TRIAL REGISTRATION: ChiCTR-INR-17012481 . (Retrospectively registered 26 August 2017).

Tropism and innate host responses of influenza A/H5N6 virus: an analysis of ex vivo and in vitro cultures of the human respiratory tract.

Since their first isolation in 2013, influenza A/H5N6 viruses have spread amongst poultry across multiple provinces in China and to Laos, Vietnam and Myanmar. So far, there have been 14 human H5N6 infections with 10 fatalities.We investigated the tropism, replication competence and cytokine induction of one human and two avian H5N6 isolates in ex vivo and in vitro cultures derived from the human respiratory tract. Virus tropism and replication were studied in ex vivo cultures of human nasopharynx, bronchus and lung. Induction of cytokines and chemokines was measured in vitro in virus-infected primary human alveolar epithelial cells.Human H5N6 virus replicated more efficiently than highly pathogenic avian influenza (HPAI) H5N1 virus and as efficiently as H1N1pdm in ex vivo human bronchus and lung and was also able to replicate in ex vivo cultures of human nasopharynx. Avian H5N6 viruses replicated less efficiently than H1N1pdm in human bronchial tissues and to similar titres as HPAI H5N1 in the lung. While the human H5N6 virus had affinity for avian-like receptors, the two avian isolates had binding affinity for both avian- and human-like receptors. All three H5N6 viruses were less potent inducers of pro-inflammatory cytokines compared with H5N1 virus.Human H5N6 virus appears better adapted to infect the human airways than H5N1 virus and may pose a significant public health threat.

Population seroprevalence of antibody to influenza A(H7N9) virus, Guangzhou, China.

BACKGROUND: Since the identification in early 2013 of severe disease caused by influenza A(H7N9) virus infection, there have been few attempts to characterize the full severity profile of human infections. Our objective was to estimate the number and severity of H7N9 infections in Guangzhou, using a serological study. METHODS: We collected residual sera from patients of all ages admitted to a hospital in the city of Guangzhou in southern China in 2013 and 2014. We screened the sera using a haemagglutination inhibition assay against a pseudovirus containing the H7 and N9 of A/Anhui/1/2013(H7N9), and samples with a screening titer ≥10 were further tested by standard hemagglutination-inhibition and virus neutralization assays for influenza A(H7N9). We used a statistical model to interpret the information on antibody titers in the residual sera, assuming that the residual sera provided a representative picture of A(H7N9) infections in the general population, accounting for potential cross-reactions. RESULTS: We collected a total of 5360 residual sera from December 2013 to April 2014 and from October 2014 to December 2014, and found two specimens that tested positive for H7N9 antibody at haemagglutination inhibition titer ≥40 and a neutralization titer ≥40. Based on this, we estimated that 64,000 (95 % credibility interval: 7300, 190,000) human infections with influenza A(H7N9) virus occurred in Guangzhou in early 2014, with an infection-fatality risk of 3.6 deaths (95 % credibility interval: 0.47, 15) per 10,000 infections. CONCLUSIONS: Our study suggested that the number of influenza A(H7N9) virus infections in Guangzhou substantially exceeded the number of laboratory-confirmed cases there, albeit with considerable imprecision. Our study was limited by the small number of positive specimens identified, and larger serologic studies would be valuable. Our analytic framework would be useful if larger serologic studies are done.

[Effect of Yunnan herb Laggera pterodonta against influenza A (H1N1) virus in vitro].

Laggera pterodonta is commonly used for treating influenza in Southwest China, especially in Yunnnan province. The main clinical effects of L. pterodonta include anti-influenza, anti-microbial, anti-inflammatory. To investigate the anti-influenza A (H1N1) virus effect of L. pterodonta, neutralization inhibition and proliferation inhibition tests were performed. MDCK culture method was used to observe the cytopathic effect (CPE) of extracts from L. pterodonta in inhibiting influenza A (H1N1) virus and haemagglutination titre of H1N1 virus in vitro. The culture medium were collected at 24 h, 48 h, 72 h, 96 h, and detected by Real time RT-PCR, in order to compare the effect of different extracts from L. pterodonta on in vitro proliferation of H1N1, virus. The result of neutralization inhibition test showed that hemagglutination titer of ethyl acetate extract were 8 times lower at 72 h; in proliferation inhibition test, hemagglutination titer of ethyl acetate extracts reduced by 2 and 4 times. According to the results of Real time RT-PCR test, the H1N1 inhibition ratio of ethyl acetate extract was 72.5%, while the proliferation inhibition ratio of ethyl acetate extract was 25.3%; as for petroleum ether extracts, the H1N1 inhibition ratio was 60.2%, while the proliferation inhibition ratio was 81.4%. In conclusion, both ethyl acetate extract and petroleum ether extract of L. pterodonta have significant neutralization and direct proliferation inhibition effects on influenza A virus.

A Platform for the Synthesis of Diverse Phosphonyl and Thiofunctionalized Sulfoxonium Ylides.

A practical strategy for the construction of diverse phosphonyl and thiofunctionalized sulfoxonium ylides via controllable monofunctionalization of hybrid I(III)/S(VI) ylides is presented. This process allows efficient P-H insertion of I(III)/S(VI) ylides under Cu catalysis, enabling the synthesis of phosphonyl sulfoxonium ylides, whereas reaction with sulfur-containing reagents including AgSCF3, KSC(S)OR, and KSCN under mild conditions resulted in α-trifluoromethylthiolation, dithiocarbanation, and thiocyanation of sulfoxonium ylides accordingly. Of note, wide substrate compatibility (108 examples), excellent efficiency (up to 99% yield), gram-scale experiments, and various product derivatizations highlight the synthetic utility of this protocol.

Peroxide derivatives as SARS-CoV-2 entry inhibitors.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 2019 (COVID-19) pandemic. Host cell invasion is mediated by the interaction of the viral spike protein (S) with human angiotensin-converting enzyme 2 (ACE2) through the receptor-binding domain (RBD). In this work, bio-layer interferometry (BLI) was used to screen a series of fifty-two peroxides, including aminoperoxides and bridged 1,2,4 - trioxolanes (ozonides), with the aim of identifying small molecules that interfere with the RBD-ACE2 interaction. We found that two compounds, compound 21 and 29, exhibit the activity to inhibit RBD-ACE2. They are further demonstrated to inhibit SARS-CoV-2 cell entry, as shown in pseudovirus assay and experiment with authentic SARS-CoV-2. A comprehensive in silico analysis was carried out to study the physicochemical and pharmacokinetic properties, revealing that both compounds have good physicochemical properties as well as good bioavailability. Our results highlight the potential of small molecules targeting RBD inhibitors as potential therapeutic drugs for COVID-19.

The tree shrew provides a useful alternative model for the study of influenza H1N1 virus.

BACKGROUND: The influenza pandemics have resulted in significant morbidity and mortality worldwide. Animal models are useful in the study of influenza virus pathogenesis. Because of various limitations in current laboratory animal models, it is essential to develop new alternative animal models for influenza virus research aimed at understanding the viral and host factors that contribute to virus infection in human. METHOD: We investigated the replicative efficiency of influenza H1N1 virus (classic strain (Influenza A/PR/8/34), seasonal influenza isolate (A/Guangzhou/GIRD/02/09) and swine-origin human influenza virus (A/Guangzhou/GIRD/07/09)) at Day1,2,4,6 and 9 p.i. using TCID50 and qPCR assay in tree shrew model. Body temperature was monitored in the morning and evening for 3 days before infection and for 14 days. Seroconversion was detected by determining the neutralizing antibody titers against the challenge viruses in the pre- and exposure serum samples collected before infection and at 14 days p.i., respectively. Lungs and tracheas of tree shews were collected at day 14 post p.i. for histopathological analysis. Lectinhistochemistry analysis was conducted to identify the distribution of SAα2,3 Gal and SAα2,6 Gal receptors in the lung and trachea. RESULTS: The infected tree shrew displayed mild or moderate systemic and respiratory symptoms and pathological changes in respiratory tracts. The human H1N1 influenza virus may replicate in the upper respiratory tract of tree shrews. Analysis of the receptors distribution in the respiratory tract of tree shrews by lectinhistochemistry showed that sialic acid (SA)α2,6-Gal receptors were widely distributed in the trachea and nasal mucosa, whereas (SA)α2,3-Gal receptor was the main receptor in the lung tissue. CONCLUSIONS: Based on these findings, tree shrew seemed to mimic well influenza virus infection in humans. We propose that tree shrews could be a useful alternative mammalian model to study pathogenesis of influenza H1N1 virus.

Epidemiology and clinical presentation of the four human parainfluenza virus types.

BACKGROUND: Human parainfluenza viruses (HPIVs) are important causes of upper respiratory tract illness (URTI) and lower respiratory tract illness (LRTI). To analyse epidemiologic and clinical characteristics of the four types of human parainfluenza viruses (HPIVs), patients with acute respiratory tract illness (ARTI) were studied in Guangzhou, southern China. METHODS: Throat swabs (n=4755) were collected and tested from children and adults with ARTI over a 26-month period, and 4447 of 4755 (93.5%) patients' clinical presentations were recorded for further analysis. RESULTS: Of 4755 patients tested, 178 (3.7%) were positive for HPIV. Ninety-nine (2.1%) samples were positive for HPIV-3, 58 (1.2%) for HPIV-1, 19 (0.4%) for HPIV-2 and 8 (0.2%) for HPIV-4. 160/178 (88.9%) HPIV-positive samples were from paediatric patients younger than 5 years old, but no infant under one month of age was HPIV positive. Seasonal peaks of HPIV-3 and HPIV-1 occurred as autumn turned to winter and summer turned to autumn. HPIV-2 and HPIV-4 were detected less frequently, and their frequency of isolation increased when the frequency of HPIV-3 and HPIV-1 declined. HPIV infection led to a wide spectrum of symptoms, and more "hoarseness" (p=0.015), "abnormal pulmonary breathing sound" (p<0.001), "dyspnoea" (p<0.001), "pneumonia" (p=0.01), and "diarrhoea" (p<0.001) presented in HPIV-positive patients than HPIV-negative patients. 10/10 (100%) HPIV-positive adult patients (≥14 years old) presented with systemic influenza-like symptoms, while 90/164 (54.9%) HPIV-positive paediatric patients (<14 years old) presented with these symptoms (p=0.005). The only significant difference in clinical presentation between HPIV types was "Expectoration" (p<0.001). Co-infections were common, with 33.3%-63.2% of samples positive for the four HPIV types also testing positive for other respiratory pathogens. However, no significant differences were seen in clinical presentation between patients solely infected with HPIV and patients co-infected with HPIV and other respiratory pathogens. CONCLUSIONS: HPIV infection led to a wide spectrum of symptoms, and similar clinical manifestations were found in the patients with four different types of HPIVs. The study suggested pathogenic activity of HPIV in gastrointestinal illness. The clinical presentation of HPIV infection may differ by patient age.