Systematic analysis of SARS-CoV-2 infection of an ACE2-negative human airway cell

Niacinamide enhances cathelicidin mediated SARS-CoV-2 membrane disruption

The continual emergence of SARS-CoV-2 variants threatens to compromise the effectiveness of worldwide vaccination programs, and highlights the need for complementary strategies for a sustainable containment plan. An effective approach is to mobilize the body's own antimicrobial peptides (AMPs), to combat SARS-CoV-2 infection and propagation. We have found that human cathelicidin (LL37), an AMP found at epithelial barriers as well as in various bodily fluids, has the capacity to neutralise multiple strains of SARS-CoV-2. Biophysical and computational studies indicate that LL37's mechanism of action is through the disruption of the viral membrane. This antiviral activity of LL37 is enhanced by the hydrotropic action of niacinamide, which may increase the bioavailability of the AMP. Interestingly, we observed an inverse correlation between LL37 levels and disease severity of COVID-19 positive patients, suggesting enhancement of AMP response as a potential therapeutic avenue to mitigate disease severity. The combination of niacinamide and LL37 is a potent antiviral formulation that targets viral membranes of various variants and can be an effective strategy to overcome vaccine escape.

2-deoxy-D-glucose as an adjunct to standard of care in the medical management of COVID-19: a proof-of-concept and dose-ranging randomised phase II clinical trial

Background

At present, no single efficacious therapeutic exists for acute COVID-19 management and a multimodal approach may be necessary. 2-deoxy-d-glucose (2-DG) is a metabolic inhibitor that has been shown to limit multiplication of SARS-CoV-2 in-vitro. We evaluated the efficacy and safety of 2-DG as adjunct to standard care in the treatment of moderate to severe COVID-19 patients.

Methods

We conducted a randomized, open-label, phase II, clinical study to evaluate the efficacy, safety, and tolerability of 2-DG administered as adjunct to standard of care (SOC). A total of 110 patients between the ages of 18 and 65 years with moderate to severe COVID-19 were included. Patients were randomized to receive 63, 90, or 126 mg/kg/day 2-DG in addition to SOC or SOC only. Times to maintaining SpO₂ ≥ 94% on room air, discharge, clinical recovery, vital signs normalisation, improvement by 1 and 2 points on WHO clinical progression scale, negative conversion on RT-PCR, requirement for intensive care, and mortality were analyzed to assess the efficacy.

Results

Patients treated with 90 mg/kg/day 2-DG plus SOC showed better outcomes. Time to maintaining SpO₂ ≥ 94% was significantly shorter in the 2-DG 90 mg compared to SOC (median 2.5 days vs. 5 days, Hazard ratio [95% confidence interval] = 2.3 [1.14, 4.64], p = 0.0201). Times to discharge from isolation ward, to clinical recovery, and to vital signs normalization were significantly shorter for the 2-DG 90 mg group. All three doses of 2-DG were well tolerated. Thirty-three (30.3%) patients reported 65 adverse events and were mostly (86%) mild.

Conclusions

2-DG 90 mg/kg/day as adjunct to SOC showed clinical benefit over SOC alone in the treatment of moderate to severe COVID-19. The promising trends observed in current phase II study is encouraging for confirmatory evaluation of the efficacy and safety of 2-DG in a larger phase III trial.

Trial registration: CTRI, CTRI/2020/06/025664. Registered 5th June 2020, http://ctri.nic.in/Clinicaltrials/pdf_generate.php?trialid=44369&EncHid=&modid=&compid=%27,%2744369det%27.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07642-6.

Potent universal-coronavirus therapeutic activity mediated by direct respiratory administration of a Spike S2 domain-specific human neutralizing monoclonal antibody

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) marks the third novel β-coronavirus to cause significant human mortality in the last two decades. Although vaccines are available, too few have been administered worldwide to keep the virus in check and to prevent mutations leading to immune escape. To determine if antibodies could be identified with universal coronavirus activity, plasma from convalescent subjects was screened for IgG against a stabilized pre-fusion SARS-CoV-2 spike S2 domain, which is highly conserved between human β-coronavirus. From these subjects, several S2-specific human monoclonal antibodies (hmAbs) were developed that neutralized SARS-CoV-2 with recognition of all variants of concern (VoC) tested (Beta, Gamma, Delta, Epsilon, and Omicron). The hmAb 1249A8 emerged as the most potent and broad hmAb, able to recognize all human β-coronavirus and neutralize SARS-CoV and MERS-CoV. 1249A8 demonstrated significant prophylactic activity in K18 hACE2 mice infected with SARS-CoV-2 lineage A and lineage B Beta, and Omicron VoC. 1249A8 delivered as a single 4 mg/kg intranasal (i.n.) dose to hamsters 12 hours following infection with SARS-CoV-2 Delta protected them from weight loss, with therapeutic activity further enhanced when combined with 1213H7, an S1-specific neutralizing hmAb. As little as 2 mg/kg of 1249A8 i.n. dose 12 hours following infection with SARS-CoV Urbani strain, protected hamsters from weight loss and significantly reduced upper and lower respiratory viral burden. These results indicate in vivo cooperativity between S1 and S2 specific neutralizing hmAbs and that potent universal coronavirus neutralizing mAbs with therapeutic potential can be induced in humans and can guide universal coronavirus vaccine development.

Kite-shaped molecules block SARS-CoV-2 cell entry at a post-attachment step.. [DOI: 10.1101/2021.05.29.446272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Anti-viral small molecules are currently lacking for treating coronavirus infection. The long development timescales for such drugs are a major problem, but could be shortened by repurposing existing drugs. We therefore screened a small library of FDA-approved compounds for potential severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antivirals using a pseudovirus system that allows a sensitive read-out of infectivity. A group of structurally-related compounds, showing moderate inhibitory activity with IC50values in the 1-5µM range, were identified. Further studies demonstrated that these ‘kite-shaped’ molecules were surprisingly specific for SARS-CoV and SARS-CoV-2 and that they acted early in the entry steps of the viral infectious cycle, but did not affect virus attachment to the cells. Moreover the compounds were able to prevent infection in both kidney- and lung-derived human cell lines. The structural homology of the hits allowed the production of a well-defined pharmacophore that was found to be highly accurate in predicting the anti-viral activity of the compounds in the screen. We discuss the prospects of repurposing these existing drugs for treating current and future coronavirus outbreaks.

Comprehensive Comparison of RNA-Seq Data of SARS-CoV-2, SARS-CoV and MERS-CoV Infections: Alternative Entry Routes and Innate Immune Responses

Background

The pathogenesis of COVID-19 emerges as complex, with multiple factors leading to injury of different organs. Some of the studies on aspects of SARS-CoV-2 cell entry and innate immunity have produced seemingly contradictory claims. In this situation, a comprehensive comparative analysis of a large number of related datasets from several studies could bring more clarity, which is imperative for therapy development.

Methods

We therefore performed a comprehensive comparative study, analyzing RNA-Seq data of infections with SARS-CoV-2, SARS-CoV and MERS-CoV, including data from different types of cells as well as COVID-19 patients. Using these data, we investigated viral entry routes and innate immune responses.

Results and Conclusion

First, our analyses support the existence of cell entry mechanisms for SARS and SARS-CoV-2 other than the ACE2 route with evidence of inefficient infection of cells without expression of ACE2; expression of TMPRSS2/TPMRSS4 is unnecessary for efficient SARS-CoV-2 infection with evidence of efficient infection of A549 cells transduced with a vector expressing human ACE2. Second, we find that innate immune responses in terms of interferons and interferon simulated genes are strong in relevant cells, for example Calu3 cells, but vary markedly with cell type, virus dose, and virus type.