Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019, causing a respiratory disease (coronavirus disease 2019, COVID-19) of varying severity in Wuhan, China, and ...subsequently leading to a pandemic. The transmissibility and pathogenesis of SARS-CoV-2 remain poorly understood. We evaluate its tissue and cellular tropism in human respiratory tract, conjunctiva, and innate immune responses in comparison with other coronavirus and influenza virus to provide insights into COVID-19 pathogenesis.
We isolated SARS-CoV-2 from a patient with confirmed COVID-19, and compared virus tropism and replication competence with SARS-CoV, Middle East respiratory syndrome-associated coronavirus (MERS-CoV), and 2009 pandemic influenza H1N1 (H1N1pdm) in ex-vivo cultures of human bronchus (n=5) and lung (n=4). We assessed extrapulmonary infection using ex-vivo cultures of human conjunctiva (n=3) and in-vitro cultures of human colorectal adenocarcinoma cell lines. Innate immune responses and angiotensin-converting enzyme 2 expression were investigated in human alveolar epithelial cells and macrophages. In-vitro studies included the highly pathogenic avian influenza H5N1 virus (H5N1) and mock-infected cells as controls.
SARS-CoV-2 infected ciliated, mucus-secreting, and club cells of bronchial epithelium, type 1 pneumocytes in the lung, and the conjunctival mucosa. In the bronchus, SARS-CoV-2 replication competence was similar to MERS-CoV, and higher than SARS-CoV, but lower than H1N1pdm. In the lung, SARS-CoV-2 replication was similar to SARS-CoV and H1N1pdm, but was lower than MERS-CoV. In conjunctiva, SARS-CoV-2 replication was greater than SARS-CoV. SARS-CoV-2 was a less potent inducer of proinflammatory cytokines than H5N1, H1N1pdm, or MERS-CoV.
The conjunctival epithelium and conducting airways appear to be potential portals of infection for SARS-CoV-2. Both SARS-CoV and SARS-CoV-2 replicated similarly in the alveolar epithelium; SARS-CoV-2 replicated more extensively in the bronchus than SARS-CoV. These findings provide important insights into the transmissibility and pathogenesis of SARS-CoV-2 infection and differences with other respiratory pathogens.
US National Institute of Allergy and Infectious Diseases, University Grants Committee of Hong Kong Special Administrative Region, China; Health and Medical Research Fund, Food and Health Bureau, Government of Hong Kong Special Administrative Region, China.
Despite causing regular seasonal epidemics with substantial morbidity, mortality and socioeconomic burden, there is still a lack of research into influenza B viruses (IBVs). In this study, we provide ...for the first time a systematic investigation on the tropism, replication kinetics and pathogenesis of IBVs in the human respiratory tract.Physiologically relevant
explant cultures of human bronchus and lung, human airway organoids, and
cultures of differentiated primary human bronchial epithelial cells and type-I-like alveolar epithelial cells were used to study the cellular and tissue tropism, replication competence and induced innate immune response of 16 IBV strains isolated from 1940 to 2012 in comparison with human seasonal influenza A viruses (IAVs), H1N1 and H3N2. IBVs from the diverged Yamagata- and Victoria-like lineages and the earlier undiverged period were included.The majority of IBVs replicated productively in human bronchus and lung with similar competence to seasonal IAVs. IBVs infected a variety of cell types, including ciliated cells, club cells, goblet cells and basal cells, in human airway organoids. Like seasonal IAVs, IBVs are low inducers of pro-inflammatory cytokines and chemokines. Most results suggested a higher preference for the conducting airway than the lower lung and strain-specific rather than lineage-specific pathogenicity of IBVs.Our results highlighted the non-negligible virulence of IBVs which require more attention and further investigation to alleviate the disease burden, especially when treatment options are limited.
Middle East Respiratory Syndrome Coronavirus (MERS-CoV) has emerged as a coronavirus infection of humans in the past 5 years. Though confined to certain geographical regions of the world, infection ...has been associated with a case fatality rate of 35%, and this mortality may be higher in ventilated patients. As there are few readily available animal models that accurately mimic human disease, it has been a challenge to ethically determine what optimum treatment strategies can be used for this disease. We used in-vitro and human ex-vivo explant cultures to investigate the effect of two immunomodulatory agents, interferon alpha and cyclosporine, singly and in combination, on MERS-CoV replication. In both culture systems the combined treatment was more effective than either agent used alone in reducing MERS-CoV replication. PCR SuperArray analysis showed that the reduction of virus replication was associated with a greater induction of interferon stimulated genes. As these therapeutic agents are already licensed for clinical use, it may be relevant to investigate their use for therapy of human MERS-CoV infection.
•The effect of interferon-α and/or cyclosporine on MERS-CoV replication was evaluated with a human ex-vivo culture model.•All treatments were able to reduce MERS-CoV replication.•The combined treatment was more effective than either agent used alone in reducing MERS-CoV replication.•The effect of the combined treatment group was associated with a greater induction of interferon stimulated genes.
Novel avian H7N9 virus emerged in China in 2013 resulting in a case fatality rate of around 39% and continues to pose zoonotic and pandemic risk. Amino acid substitutions in PB2 protein were shown to ...influence the pathogenicity and transmissibility of H7N9 following experimental infection of ferrets and mice. In this study, we evaluated the role of amino acid substitution PB2-627K or compensatory changes at PB2-591K and PB2-701N, on the tropism and replication competence of H7N9 viruses for human and swine respiratory tracts using ex vivo organ explant cultures. Recombinant viruses of A/Shanghai/2/2013 (rgH7N9) and its mutants with PB2-K627E, PB2-K627E + Q591K and PB2-K627E + D701N were generated by plasmid-based reverse genetics. PB2-E627K was essential for efficient replication of rgH7N9 in ex vivo cultures of human and swine respiratory tracts. Mutant rgPB2-K627E + D701N replicated better than rgPB2-K627E in human lung but not as well as rgH7N9 virus. The rgPB2-K627E mutant failed to replicate in human type I-like pneumocytes (ATI) and peripheral blood monocyte-derived macrophages (PMϕ) at 37 °C while the compensatory mutant rgPB2-K627E + Q591K and rgPB2-K627E + D701N had partly restored replication competence in PMϕ. Our results demonstrate that PB2-E627K was important for efficient replication of influenza H7N9 in both human and swine respiratory tracts.
•Simvastatin inhibited virus replication and cytokine production by H5N1 virus.•Zometa and FPT inhibitor III inhibited both H5N1 and H1N1 replication.•FPT inhibitor III is a strong immuno-regulator ...during H5N1 infection.•Protein farnesylation plays a role in cytokine induction by H5N1 virus.
Highly pathogenic H5N1 viruses continue to transmit zoonotically, with mortality higher than 60%, and pose a pandemic threat. Antivirals remain the primary choice for treating H5N1 diseases and have their limitations. Encouraging findings highlight the beneficial effects of combined treatment of host targeting agents with immune-modulatory activities. This study evaluated the undefined roles of sterol metabolic pathway in viral replication and cytokine induction by H5N1 virus in human alveolar epithelial cells. The suppression of the sterol biosynthesis by Simvastatin in human alveolar epithelial cells led to reduction of virus replication and cytokine production by H5N1 virus. We further dissected the antiviral role of different regulators of the sterol metabolism, we showed that Zometa, FPT inhibitor III, but not GGTI-2133 had anti-viral activities against both H5N1 and H1N1 viruses. More importantly, FPT inhibitor III treatment significantly suppressed cytokine production by H5N1 virus infected alveolar epithelial cells. Since both viral replication itself and the effects of viral hyper-induction of cytokines contribute to the immunopathology of severe H5N1 disease, our findings highlights the therapeutic potential of FPT inhibitor III for severe human H5N1 diseases. Furthermore, our study is the first to dissect the roles of different steps in the sterol metabolic pathway in H5N1 virus replication and cytokine production.
to identify the antenatal taboos commonly practised by pregnant Hong Kong Chinese women; to explore the health beliefs behind these taboos; and to examine how pregnant women perceived and reacted to ...the cultural tradition.
general ethnography and in-depth interviews, followed by a quantitative self-reported survey.
Antenatal clinic of a university-affiliated hospital in Hong Kong.
consecutive samples of 60 women for in-depth interviews, and 832 women for the survey.
an inventory on the adherence and attitude towards antenatal taboos, and the Beck Depression Inventory that measures severity of depression.
antenatal taboos were still commonly observed by contemporary Chinese women. Miscarriage, fetus malformation and fetal ill-health were the key cultural fears that drove contemporary Chinese women to observe the traditional taboos. About one-quarter and one-tenth of the women, respectively, felt unhappy and disputed with their families about the taboos. These women had significantly higher levels of depression in late pregnancy and during childbirth.
health-care practitioners should be aware of the benefits and risks of traditional antenatal taboos on maternal health. Although some taboos can be socio-morally protective, the tension created by the observation of cultural tradition in modernity may impair maternal psychological well-being. Health-care providers in Western countries should be vigilant of the complex cultural tension faced by migrant Chinese mothers.
The three-dimensional (3D) structure of chromatin is intrinsically associated with gene regulation and cell function
. Methods based on chromatin conformation capture have mapped chromatin structures ...in neuronal systems such as in vitro differentiated neurons, neurons isolated through fluorescence-activated cell sorting from cortical tissues pooled from different animals and from dissociated whole hippocampi
. However, changes in chromatin organization captured by imaging, such as the relocation of Bdnf away from the nuclear periphery after activation
, are invisible with such approaches
. Here we developed immunoGAM, an extension of genome architecture mapping (GAM)
, to map 3D chromatin topology genome-wide in specific brain cell types, without tissue disruption, from single animals. GAM is a ligation-free technology that maps genome topology by sequencing the DNA content from thin (about 220 nm) nuclear cryosections. Chromatin interactions are identified from the increased probability of co-segregation of contacting loci across a collection of nuclear slices. ImmunoGAM expands the scope of GAM to enable the selection of specific cell types using low cell numbers (approximately 1,000 cells) within a complex tissue and avoids tissue dissociation
. We report cell-type specialized 3D chromatin structures at multiple genomic scales that relate to patterns of gene expression. We discover extensive 'melting' of long genes when they are highly expressed and/or have high chromatin accessibility. The contacts most specific of neuron subtypes contain genes associated with specialized processes, such as addiction and synaptic plasticity, which harbour putative binding sites for neuronal transcription factors within accessible chromatin regions. Moreover, sensory receptor genes are preferentially found in heterochromatic compartments in brain cells, which establish strong contacts across tens of megabases. Our results demonstrate that highly specific chromatin conformations in brain cells are tightly related to gene regulation mechanisms and specialized functions.
ObjectiveThe purpose of this study was to identify genetic variants underlying the considerable individual differences in response to antidepressant treatment. The authors performed a genome-wide ...association analysis of improvement of depression severity with two antidepressant drugs.
MethodHigh-quality Illumina Human610-quad chip genotyping data were available for 706 unrelated participants of European ancestry treated for major depression with escitalopram (N=394) or nortriptyline (N=312) over a 12-week period in the Genome-Based Therapeutic Drugs for Depression (GENDEP) project, a partially randomized open-label pharmacogenetic trial.
ResultsSingle nucleotide polymorphisms in two intergenic regions containing copy number variants on chromosomes 1 and 10 were associated with the outcome of treatment with escitalopram or nortriptyline at suggestive levels of significance and with a high posterior likelihood of true association. Drug-specific analyses revealed a genome-wide significant association between marker rs2500535 in the uronyl 2-sulphotransferase gene and response to nortriptyline. Response to escitalopram was best predicted by a marker in the interleukin-11 (IL11) gene. A set of 72 a priori-selected candidate genes did not show pharmacogenetic associations above a chance level, but an association with response to escitalopram was detected in the interleukin-6 gene, which is a close homologue of IL11.
ConclusionsWhile limited statistical power means that a number of true associations may have been missed, these results suggest that efficacy of antidepressants may be predicted by genetic markers other than traditional candidates. Genome-wide studies, if properly replicated, may thus be important steps in the elucidation of the genetic basis of pharmacological response.
Healthcare workers (HCWs) use personal protective equipment (PPE) in Ebola virus disease (EVD) situations. However, preventing the contamination of HCWs and the environment during PPE removal ...crucially requires improved strategies. This study aimed to compare the efficacy of three PPE ensembles, namely, Hospital Authority (HA) Standard Ebola PPE set (PPE1), Dupont Tyvek Model, style 1422A (PPE2), and HA isolation gown for routine patient care and performing aerosol-generating procedures (PPE3) to prevent EVD transmission by measuring the degree of contamination of HCWs and the environment.
A total of 59 participants randomly performed PPE donning and doffing. The trial consisted of PPE donning, applying fluorescent solution on the PPE surface, PPE doffing of participants, and estimation of the degree of contamination as indicated by the number of fluorescent stains on the working clothes and environment. Protocol deviations during PPE donning and doffing were monitored.
PPE2 and PPE3 presented higher contamination risks than PPE1. Environmental contaminations such as those originating from rubbish bin covers, chairs, faucets, and sinks were detected. Procedure deviations were observed during PPE donning and doffing, with PPE1 presenting the lowest overall deviation rate (%) among the three PPE ensembles (
0.05).
Contamination of the subjects' working clothes and surrounding environment occurred frequently during PPE doffing. Procedure deviations were observed during PPE donning and doffing. Although PPE1 presented a lower contamination risk than PPE2 and PPE3 during doffing and protocol deviations, the design of PPE1 can still be further improved. Future directions should focus on designing a high-coverage-area PPE with simple ergonomic features and on evaluating the doffing procedure to minimise the risk of recontamination. Regular training for users should be emphasised to minimise protocol deviations, and in turn, guarantee the best protection to HCWs.
Background Obesity is an important risk factor for OSA. This study aimed to assess the effect of weight reduction through a lifestyle modification program (LMP) on patients with moderate to severe ...OSA. Methods This was a parallel group, randomized controlled trial. Altogether, 104 patients with moderate to severe OSA diagnosed on portable home sleep monitoring were randomized to receive a dietician-led LMP or usual care for 12 months. The primary outcome was reduction of apnea-hypopnea index (AHI) at 12 months as assessed by portable home sleep monitoring. Results In the intention-to-treat analysis (ITT), LMP (n = 61) was more effective in reducing AHI from baseline (16.9% fewer events in the LMP group vs 0.6% more events in the control group, P = .011). LMP was more effective in reducing BMI (–1.8 kg/m2 , 6.0% of the initial BMI; –0.6 kg/m2 , 2.0% of the initial BMI in control group; P < .001). The reduction in daytime sleepiness as assessed by Epworth Sleepiness Scale was not significant in ITT but was more in the LMP group (–3.5 in the LMP group vs –1.1 in the control group, P = .004) by treatment per protocol analysis. There was modest improvement in mental health in the Short Form Health Survey. Eating behavior was improved with increased intake of protein and fiber. These changes were observed 4 months after the initial intensive diet counseling and persisted at 12 months. Conclusions LMP was effective in reducing the severity of OSA and daytime sleepiness. The beneficial effect was sustained in 12 months. Trial Registry ClinicalTrials.gov; No.: NCT01384760; URL: www.clinicaltrials.gov
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