Perspectives for the optimization and utility of the rotavirus reverse genetics system

Following Kobayashi and colleagues' seminal paper in 20171, in the past four years the rotavirus (RV) field has witnessed a burst in research and publications based on the use of a fully plasmid-based RV reverse genetics systems and subsequent modifications2,3. However, in most cases, the rotaviral strain under interrogation has been the prototypic simian RV SA11-L2 strain (G3P[2]). Of note, a variety of other weakly-to-modestly replication-competent animal and human RV strains, bioluminescent and fluorescent reporter viruses, and clinical isolates of human RVs have proved hard or impossible to rescue using the original reverse genetics system2,4, highlighting a critical need to further enhance the recovery efficiency and expand the rescue tool kit. A number of further modifications of the initial reverse genetics system have enabled the rescue of other RV strains such as the human RV KU and CDC-9 strains, and a murine RV D6/2-like strain4,5. Here, we discuss future possible modifications of existing RV reverse genetics systems to further increase efficiency based on past experience with the improvement of influenza A virus recovery. The development of RV to accommodate the insertion and expression of heterologous sequences has substantial potential in the design of next-generation RV vaccine candidates and enteric viral vectors.

Micromagnetic simulation of microstructure effect for binary-main-phase Nd-Ce-Fe-B magnets

We investigate the magnetic properties of a chemically heterogeneous binary-main-phase (BMP) Nd-Ce-Fe-B magnet with a core-shell structure via micromagnetic simulation. It is found that the coercivity strongly depends on the shell thickness. The BMP magnet's coercivity initially increases and then decreases with increasing Nd-rich shell thickness, and so there is the optimal shell thickness which shows the maximum coercivity for any given Ce concentration. The simulation shows the significant difference in coercivity and maximum energy product between the BMP and single-main-phase magnets. Notably, the magnetization reversal mechanism of the BMP magnet is revealed in the simulation. Local reversals in the BMP magnet first occur in the Ce-rich shells, followed by the Nd-rich cores. Then, the magnetization in Ce-rich core/Nd-rich shell typed grains is switched after reversed magnetization of all the Nd-rich core/Ce-rich shell typed grains. The BMP magnet represents a further increased coercivity for a larger GB thickness, which can be well explained by a maximum stray field.

Mesalamine Reduces Intestinal ACE2 Expression Without Modifying SARS-CoV-2 Infection or Disease Severity in Mice

Introduction

Coronavirus Disease 2019 (COVID-19) is an ongoing public health crisis that has sickened or precipitated death in millions. The etiologic agent of COVID-19, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), infects the intestinal epithelium, and can induce GI symptoms similar to the human inflammatory bowel diseases (IBD). An international surveillance epidemiology study (SECURE-IBD) reported that the standardized mortality ratio trends higher in IBD patients (1.5-1.8) and that mesalamine/sulfasalazine therapy correlates with poor outcome. The goal of our study was to experimentally address the relationship between mesalamine and SARS-CoV-2 entry, replication, and/or pathogenesis.

Methods

Viral infection was performed with a chimeric vesicular stomatitis virus expressing SARS-CoV-2 spike protein and EGFP (VSV-SARS-CoV-2) and SARS-CoV-2 virus derived from an infectious cDNA clone of 2019n-CoV/USA_WA1/2020. Primary human ileal spheroids derived from healthy donors were grown as 3D spheroids or on 2D transwells. We assessed the effect of 10 mM mesalamine (Millipore Sigma) on viral RNA levels, as well as the expression of the SARS-CoV-2 receptor angiotensin II-converting enzyme 2 (ACE2), Transmembrane Serine Protease 2 (TMPRSS2), TMPRSS4, Cathepsin B (CTSB) and CTSL by qRT-PCR. 8-12 week old K18-ACE2 were treated orally with PBS or mesalamine at 200 mg/kg daily. Mice were inoculated intranasally with 1Ã-10 ³ FFU of SARS-CoV-2. Mice were weighed daily and viral titers were determined 7 days post infection (dpi) by qRT-PCR. For the intestinal viral entry model, VSV-SARS-CoV-2 was injected into a ligated intestinal loop of anesthetized K18-ACE2 mice and tissues were harvested 6 hours post-infection.

Results

We found no change in viral RNA levels in human intestinal epithelial cells in response to mesalamine. Expression of ACE2 was reduced following mesalamine treatment in enteroids, while CTSL expression was increased. Mice receiving mesalamine lost weight at similar rates compared to mice receiving vehicle control. Mesalamine treatment did not change viral load in the lung, heart, or intestinal tissues harvested at 7 dpi. Pretreatment with mesalamine did not modulate intestinal entry of the chimeric VSV-SARS-CoV-2 in K18-ACE2 mice.

Conclusions

Mesalamine did not alter viral entry, replication, or pathogenesis in vitro or in mouse models. Mesalamine treatment reduced expression of the viral receptor ACE2 while concurrently increasing CTSL expression in human ileum organoids.

SARS-CoV-2 exacerbates proinflammatory responses in myeloid cells through C-type lectin receptors and Tweety family member 2

Despite mounting evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) engagement with immune cells, most express little, if any, of the canonical receptor of SARS-CoV-2, angiotensin-converting enzyme 2 (ACE2). Here, using a myeloid cell receptor-focused ectopic expression screen, we identified several C-type lectins (DC-SIGN, L-SIGN, LSECtin, ASGR1, and CLEC10A) and Tweety family member 2 (TTYH2) as glycan-dependent binding partners of the SARS-CoV-2 spike. Except for TTYH2, these molecules primarily interacted with spike via regions outside of the receptor-binding domain. Single-cell RNA sequencing analysis of pulmonary cells from individuals with coronavirus disease 2019 (COVID-19) indicated predominant expression of these molecules on myeloid cells. Although these receptors do not support active replication of SARS-CoV-2, their engagement with the virus induced robust proinflammatory responses in myeloid cells that correlated with COVID-19 severity. We also generated a bispecific anti-spike nanobody that not only blocked ACE2-mediated infection but also the myeloid receptor-mediated proinflammatory responses. Our findings suggest that SARS-CoV-2-myeloid receptor interactions promote immune hyperactivation, which represents potential targets for COVID-19 therapy.

JIB-04 has broad-spectrum antiviral activity and inhibits SARS-CoV-2 replication and coronavirus pathogenesis

Pathogenic coronaviruses represent a major threat to global public health. Here, using a recombinant reporter virus-based compound screening approach, we identified several small-molecule inhibitors that potently block the replication of the newly emerged severe acute respiratory syndrome virus 2 (SARS-CoV-2). Among them, JIB-04 inhibited SARS-CoV-2 replication in Vero E6 cells with an EC50 of 695 nM, with a specificity index of greater than 1,000. JIB-04 showed in vitro antiviral activity in multiple cell types against several DNA and RNA viruses, including porcine coronavirus transmissible gastroenteritis virus. In an in vivo porcine model of coronavirus infection, administration of JIB-04 reduced virus infection and associated tissue pathology, which resulted in improved weight gain and survival. These results highlight the potential utility of JIB-04 as an antiviral agent against SARS-CoV-2 and other viral pathogens.

Integration of full divertor detachment with improved core confinement for tokamak fusion plasmas

Divertor detachment offers a promising solution to the challenge of plasma-wall interactions for steady-state operation of fusion reactors. Here, we demonstrate the excellent compatibility of actively controlled full divertor detachment with a high-performance (βN ~ 3, H98 ~ 1.5) core plasma, using high-βp (poloidal beta, βp > 2) scenario characterized by a sustained core internal transport barrier (ITB) and a modest edge transport barrier (ETB) in DIII-D tokamak. The high-βp high-confinement scenario facilitates divertor detachment which, in turn, promotes the development of an even stronger ITB at large radius with a weaker ETB. This self-organized synergy between ITB and ETB, leads to a net gain in energy confinement, in contrast to the net confinement loss caused by divertor detachment in standard H-modes. These results show the potential of integrating excellent core plasma performance with an efficient divertor solution, an essential step towards steady-state operation of reactor-grade plasmas.

Cholesterol 25-hydroxylase suppresses SARS-CoV-2 replication by blocking membrane fusion

Cholesterol 25-hydroxylase (CH25H) is an interferon (IFN)-stimulated gene that shows broad antiviral activities against a wide range of enveloped viruses. Here, using an IFN-stimulated gene screen against vesicular stomatitis virus (VSV)-SARS-CoV and VSV-SARS-CoV-2 chimeric viruses, we identified CH25H and its enzymatic product 25-hydroxycholesterol (25HC) as potent inhibitors of SARS-CoV-2 replication. Internalized 25HC accumulates in the late endosomes and potentially restricts SARS-CoV-2 spike protein catalyzed membrane fusion via blockade of cholesterol export. Our results highlight one of the possible antiviral mechanisms of 25HC and provide the molecular basis for its therapeutic development.

When STING Meets Viruses: Sensing, Trafficking and Response

To effectively defend against microbial pathogens, the host cells mount antiviral innate immune responses by producing interferons (IFNs), and hundreds of IFN-stimulated genes (ISGs). Upon recognition of cytoplasmic viral or bacterial DNAs and abnormal endogenous DNAs, the DNA sensor cGAS synthesizes 2',3'-cGAMP that induces STING (stimulator of interferon genes) undergoing conformational changes, cellular trafficking, and the activation of downstream factors. Therefore, STING plays a pivotal role in preventing microbial pathogen infection by sensing DNAs during pathogen invasion. This review is dedicated to the recent advances in the dynamic regulations of STING activation, intracellular trafficking, and post-translational modifications (PTMs) by the host and microbial proteins.

Neutralizing Antibody and Soluble ACE2 Inhibition of a Replication-Competent VSV-SARS-CoV-2 and a Clinical Isolate of SARS-CoV-2

Antibody-based interventions against SARS-CoV-2 could limit morbidity, mortality, and possibly transmission. An anticipated correlate of such countermeasures is the level of neutralizing antibodies against the SARS-CoV-2 spike protein, which engages with host ACE2 receptor for entry. Using an infectious molecular clone of vesicular stomatitis virus (VSV) expressing eGFP as a marker of infection, we replaced the glycoprotein gene (G) with the spike protein of SARS-CoV-2 (VSV-eGFP-SARS-CoV-2) and developed a high-throughput-imaging-based neutralization assay at biosafety level 2. We also developed a focus-reduction neutralization test with a clinical isolate of SARS-CoV-2 at biosafety level 3. Comparing the neutralizing activities of various antibodies and ACE2-Fc soluble decoy protein in both assays revealed a high degree of concordance. These assays will help define correlates of protection for antibody-based countermeasures and vaccines against SARS-CoV-2. Additionally, replication-competent VSV-eGFP-SARS-CoV-2 provides a tool for testing inhibitors of SARS-CoV-2 mediated entry under reduced biosafety containment.

[Safety analysis of 12 241 infants inoculated in three sites of diphtheria, tetanus, acellular pertussis and haemophilus influenzae type b combined vaccine in Chaoyang District of Beijing]

Objective: To observe the adverse reactions of Diphtheria, Tetanus, Acellular Pertussis and Haemophilus Influenzae Type b Combined Vaccine conjugate vaccine at the anterolateral thigh muscle, upper arm deltoid muscle and upper gluteal region. Methods: A total of 12 241 infants who were voluntarily vaccinated DTaP-Hib from April 2015 to April 2019 in Beijing were selected for the study. DTaP-Hib vaccine is recommended for 3, 4, 5 months of age for basic immunization and 18 to 24 months of age to strengthen immunization. Subjects were divided into the groups of lateral thigh muscle, the upper arm deltoid and upper gluteal region according to the actual inoculation sites. Adverse reactions were collected within 30 minutes and 7 days after each does of vaccination at different sites and compared between three groups. The incidence of adverse reactions at the three different inoculation sites was compared by Chi-square test. Results: A total of 12 241 infants and toddlers received combined DTaP-Hib and 35 027 doses of DTaP-Hib were investigated. The number and of lateral thigh muscles, upper arm deltoids and gluteal muscles were 3 461 infants and 11 129 doses, 2 659 infants and 7 957 doses, 6 121 infants and 15 941 doses respectively. A total of 2 489 adverse reactions occurred. The incidence of adverse reactions was 7.11%. The incidence of adverse reactions in deltoid muscle of upper arm was 9.69%（771 doses）, which was higher than that in gluteal muscle (7.58%, 1 211 doses) and anterolateral muscle of thigh (4.56%, 507 doses). The incidence of mild, moderate and severe adverse reactions in the upper arm deltoid group were higher than those in the other two groups. The incidence rates were 4.85% (386 doses), 3.77% (300 doses) and 1.07% (85 doses) respectively. The differences between groups were statistically significant（P<0.001）. The total adverse reactions of the three doses of basic immunization and the fourth dose of enhanced immunization had the same trend in different parts. The incidence of adverse reactions was in the order of the upper arm deltoid injection, upper gluteal injection and lateral thigh muscle injection from high to low. The differences were statistically significant (P<0.001). Conclusion: The incidence of adverse reactions of DTaP-Hib vaccination in three different sites was low, which confirmed that the DTaP-Hib vaccination got expected safety regardless of the sites of inoculation. The lateral femoral muscle group had the lowest incidence of adverse reactions, hence it should be preferred as the inoculation site of DTaP-Hib vaccination.

[Characteristics on molecular epidemiology of Brucella melitensis in Jiangxi province]

Objective: To understand the molecular characteristics and correlation among isolated strains of Brucella melitensis (BM) so as to improve the strategies on prevention and control of the disease in Jiangxi province. Methods: A total of 25 strains of BM isolated from human in 17 counties of Jiangxi province were analyzed by multiple locus variable-number tandem repeat analysis (MLVA) method. Results: A total of 25 strains of BM were classified into 24 independent genotypes with similarities between 67.00% and 100.00% and Simpson index between 0.000 and 0.773. There were 3 genotypes in MLVA8, including 60.00% (15/25) as 42 genotype, 32.00% (8/25) as 43 genotype, and 8.00% (2/25) as 63 genotype, respectively. There were 7 genotypes in MLVA11 identified, with 116 genotype and 125 genotype the main genotypes, accounting for 56.00% (14/25) of all the identified strains. Conclusions: Genes from all the 25 strains of BM that isolated from human being were with high genetic diversities, and various, genotypes. However, no obvious epidemiological correlation was noticed among these strains, indicating the complexity of the source of infection on Brucella in Jiangxi province.

Retinoic Acid and Lymphotoxin Signaling Promote Differentiation of Human Intestinal M Cells

BACKGROUND & AIMS

Intestinal microfold (M) cells are a unique subset of intestinal epithelial cells in the Peyer's patches that regulate mucosal immunity, serving as portals for sampling and uptake of luminal antigens. The inability to efficiently develop human M cells in cell culture has impeded studies of the intestinal immune system. We aimed to identify signaling pathways required for differentiation of human M cells and establish a robust culture system using human ileum enteroids.

METHODS

We analyzed transcriptome data from mouse Peyer's patches to identify cell populations in close proximity to M cells. We used the human enteroid system to determine which cytokines were required to induce M-cell differentiation. We performed transcriptome, immunofluorescence, scanning electron microscope, and transcytosis experiments to validate the development of phenotypic and functional human M cells.

RESULTS

A combination of retinoic acid and lymphotoxin induced differentiation of glycoprotein 2-positive human M cells, which lack apical microvilli structure. Upregulated expression of innate immune-related genes within M cells correlated with a lack of viral antigens after rotavirus infection. Human M cells, developed in the enteroid system, internalized and transported enteric viruses, such as rotavirus and reovirus, across the intestinal epithelium barrier in the enteroids.

CONCLUSIONS

We identified signaling pathways required for differentiation of intestinal M cells, and used this information to create a robust culture method to develop human M cells with capacity for internalization and transport of viruses. Studies of this model might increase our understanding of antigen presentation and the systemic entry of enteric pathogens in the human intestine.

Is SARS-CoV-2 Also an Enteric Pathogen With Potential Fecal-Oral Transmission? A COVID-19 Virological and Clinical Review

In as few as 3 months, coronavirus disease 2019 (COVID-19) has spread and ravaged the world at an unprecedented speed in modern history, rivaling the 1918 flu pandemic. Severe acute respiratory syndrome coronavirus-2, the culprit virus, is highly contagious and stable in the environment and transmits predominantly among humans via the respiratory route. Accumulating evidence suggest that this virus, like many of its related viruses, may also be an enteric virus that can spread via the fecal-oral route. Such a hypothesis would also contribute to the rapidity and proliferation of this pandemic. Here we briefly summarize what is known about this family of viruses and literature basis of the hypothesis that severe acute respiratory syndrome coronavirus-2 is capable of infecting the gastrointestinal tract and shedding in the environment for potential human-to-human transmission.

Effectiveness of Zhong-Yong thinking based dialectical behavior therapy group skills training versus supportive group therapy for lowering suicidal risks in Chinese young adults: A randomized controlled trial with a 6-month follow-up

BACKGROUND

Dialectical behavior therapy (DBT) is a first-line treatment for the prevention of suicide. Zhong-Yong thinking could be viewed as a Chinese way of dialectical thinking, has long been a culturally dictating thinking style in China. To enhance cultural adaptability, we integrated Zhong-Yong thinking into DBT group skills training and examined its efficacy in suicidal prevention compared with a supportive group therapy and a wait-list group in high-risk suicidal Chinese college students.

METHODS

A total of 97 suicidal participants were randomized to either Zhong-Yong thinking based DBT group skills training (DBT_ZYT , n = 33), or supportive group therapy (SGT; n = 32), or wait-list group (WL; n = 32). DBT_ZYT was a 12-week program based on Zhong-Yong thinking instead of dialectical thinking, coaching participants mindfulness, emotion regulation, distress tolerance, and interpersonal effectiveness. Supportive group therapy was a 12-week program aiming at improving interpersonal effectiveness and emotion regulation skills. Outcome measures were assessed at pre- and post-treatment and 6-month follow-up.

RESULTS

At post-treatment measures, the levels of suicidal ideation, hopelessness, psychache symptoms, and general psychopathology had significantly decreased in both intervention groups; at the 6-month follow-up measures, the intervention effects were better maintained in the DBT_ZYT group rather than in the SGT group. Specifically, DBT_ZYT was more effective in relieving participants' long-term obsessive-compulsive, anxiety, hostility, phobic, psychotic, and additional symptoms.

CONCLUSIONS

Zhong-Yong thinking not only could integrate with DBT skills training in Chinese young adult population, but also has special strength in enhancing DBT's efficacy.

Neutralizing antibody and soluble ACE2 inhibition of a replication-competent VSV-SARS-CoV-2 and a clinical isolate of SARS-CoV-2

Antibody-based interventions against SARS-CoV-2 could limit morbidity, mortality, and possibly disrupt epidemic transmission. An anticipated correlate of such countermeasures is the level of neutralizing antibodies against the SARS-CoV-2 spike protein, yet there is no consensus as to which assay should be used for such measurements. Using an infectious molecular clone of vesicular stomatitis virus (VSV) that expresses eGFP as a marker of infection, we replaced the glycoprotein gene (G) with the spike protein of SARS-CoV-2 (VSV-eGFP-SARS-CoV-2) and developed a high-throughput imaging-based neutralization assay at biosafety level 2. We also developed a focus reduction neutralization test with a clinical isolate of SARS-CoV-2 at biosafety level 3. We compared the neutralizing activities of monoclonal and polyclonal antibody preparations, as well as ACE2-Fc soluble decoy protein in both assays and find an exceptionally high degree of concordance. The two assays will help define correlates of protection for antibody-based countermeasures including therapeutic antibodies, immune γ-globulin or plasma preparations, and vaccines against SARS-CoV-2. Replication-competent VSV-eGFP-SARSCoV-2 provides a rapid assay for testing inhibitors of SARS-CoV-2 mediated entry that can be performed in 7.5 hours under reduced biosafety containment.