Arylcoumarin perturbs SARS-CoV-2 pathogenesis by targeting the S-protein/ACE2 interaction.

The vaccination drive against COVID-19 worldwide was quite successful. However, the second wave of infections was even more disastrous. There was a rapid increase in reinfections and human deaths due to the appearance of new SARS-CoV-2 variants. The viral genome mutations in the variants were acquired while passing through different human hosts that could escape antibodies in convalescent or vaccinated individuals. The treatment was based on oxygen supplements and supportive protocols due to the lack of a specific drug. In this study, we identified three lead inhibitors of arylated coumarin derivatives 4,6,8-tri(naphthalen-2-yl)-2H-chromen-2-one (NF1), 8-(4-hydroxyphenyl)-4,6-di(naphthalen-2-yl)-2H-chromen-2-one (NF12) and 8-(4-hydroxyphenyl)-3,6-di(naphthalen-2-yl)-2H-chromen-2-one (NF-13) that showed higher binding affinity towards the junction of SARS-CoV-2 spike glycoprotein (S-protein) and human angiotensin-converting enzyme 2 (ACE2) receptor. Using molecular docking analysis, we identified the putative binding sites of these potent inhibitors. Notably, molecular dynamics (MD) simulation and MM-PBSA studies confirmed that these inhibitors have the potential ability to bind Spike-protein/ACE2 protein complex with minimal energy. Further, the two major concerns are an adaptive mutation of spike proteins- N501Y and D614G which displayed strong affinity towards NF-13 in docking analysis. Additionally, in vitro and in vivo studies are required to confirm the above findings and develop the inhibitors as potential drugs against SARS-CoV-2.

Correlation between placental histopathology and perinatal outcome in COVID-19.

Objectives: An alarming rate of adverse perinatal outcomes as well as maternal deaths has been reported worldwide during this pandemic. It would be prudent to start thinking on the lines of acute or chronic intrauterine fetal hypoxia due to placental microvascular pathology or villitis caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Autopsy studies of deceased patients with severe COVID-19 have revealed the presence of diffuse pulmonary alveolar damage, thrombosis, and microvascular injuries. It is expected that similar pathological features such as microvascular injuries could be found in the placenta of infected pregnant women. Materials and Methods: Placentas of singleton pregnancies from 42 SARS-CoV-2 positive mothers delivered at term were submitted for histopathological examination. Those with multifetal gestation, hypertensive disorder, fetal growth restriction, structural or chromosomal anomalies in the fetus, thrombophilia, prolonged prelabor rupture of membranes, and placenta accreta spectrum were excluded from the study. Histopathological examination was done by two pathologists independently and only those results concurred by both were reported. Histopathological features and corresponding neonatal outcome were analyzed. Results: Reports of 42 placentas from patients with SARS-CoV-2, delivered at term (37-40 weeks) were analyzed in our study. Features of maternal vascular malperfusions (MVM) were present in 45% (n = 19) cases. Features of fetal vascular malperfusions (FVM) were present in 23.8% (n = 10) cases. There were 47.6% (n = 20) cases showing at least one feature of acute inflammatory pathology (AIP) and 42.8% (n = 18) showing features of chronic inflammatory pathology (CIP). Neonatal respiratory distress syndrome was found in 19% (n = 8) of the neonates. Correspondingly, nearly all placentas (n = 7) of these neonates showed features of MVM, FVM, AIP and CIP. There was no maternal or neonatal mortality in our study group. Conclusion: The main findings of our study include maternal as well as fetal vascular malperfusions and placental inflammatory pathology. These findings provide an outline for better understanding of etiological factors and pathogenesis of adverse perinatal outcomes in SARS-CoV-2 infection.

Targeting virus-host interaction by novel pyrimidine derivative: an in silico approach towards discovery of potential drug against COVID-19.

The entire human population over the globe is currently facing appalling conditions due to the spread of infection from coronavirus disease-2019 (COVID-19). The spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) present on the surface of the virion mediates the virus entry into the host cells and therefore is targeted by several scientific groups as a novel drug target site. The spike glycoprotein binds to the human angiotensin-converting enzyme-2 (hACE2) cell surface receptor abundantly expressed in lung tissues, and this binding phenomenon is a primary determinant of cell tropism and pathogenesis. The binding and internalization of the virus is the primary and most crucial step in the process of infection, and therefore the molecules targeting the inhibition of this process certainly hold a significant therapeutic value. Thus, we systematically applied the computational techniques to identify the plausible inhibitor from a chosen set of well characterized diaryl pyrimidine analogues which may disrupt interfacial interaction of spike glycoprotein (S) at the surface of hACE2. Using molecular docking, molecular dynamics (MD) simulation and binding free energy calculation, we have identified AP-NP (2-(2-amino-5-(naphthalen-2-yl)pyrimidin-4-yl)phenol), AP-3-OMe-Ph (2-(2-amino-5-(3-methoxyphenyl)pyrimidin-4-yl)phenol) and AP-4-Me-Ph (2-(2-amino-5-(p-tolyl) pyrimidin-4-yl)phenol) from a group of diaryl pyrimidine derivatives which appears to bind at the interface of the hACE2-S complex with low binding free energy. Thus, pyrimidine derivative AP-NP may be explored as an effective inhibitor for hACE2-S complex. Furthermore, in vitro and in vivo studies will strengthen the use of these inhibitors as suitable drug candidates against SARS-COV-2. Communicated by Ramaswamy H. Sarma.

In silico identification and validation of triarylchromones as potential inhibitor against main protease of severe acute respiratory syndrome coronavirus 2.

The ongoing pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused COVID-19 has emerged as a severe threat to the life of human kind. The identification and designing of appropriate and reliable drug molecule for the treatment of COVID-19 patients is the pressing need of the present time. Among different drug targets, the main protease of SARS-CoV-2 is being considered as most effective target. In addition to the drug repurposing, different compounds of natural as well as synthetic origins are being investigated for their efficacy against different drug targets of SARS-CoV-2 virus. In that context, the chromone based natural flavonols have also exhibited significant antiviral properties against different targets of SARS-CoV-2. The in silico studies presented here discloses the efficacy of triarylchromones (TAC) as potential inhibitor against main protease of SARS-CoV-2. The molecular docking and ADMET study performed using 14 arylchromones which could easily be accessed through simple synthetic protocols, revealed best binding affinities in case of TAC-3 (-11.2 kcal/mol), TAC-4 (-10.5 kcal/mol), TAC-6 (-11.2 kcal/mol), TAC-7 (-10.0 kcal/mol). Additional validation studies including molecular dynamics simulation and binding energy calculation using MMGBSA for protein ligand complex for 100 ns revealed the best binding interaction of TAC-3, TAC-4, TAC-6, TAC-7 against main protease of SARS-CoV-2. Moreover, the in vitro and preclinical validation of identified compounds will help us to understand the molecular mechanisms of regulation of TACs against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

Stress and Anxiety Management During the COVID-19 Pandemic (Lessons Learnt from a Cohort of Orthopaedic Registrars Redeployed to ITU).

BACKGROUND: Working during the coronavirus pandemic has had a significant impact on health care workers. A group of orthopaedic trainees at Royal Gwent Hospital, UK, were redeployed to intensive therapy unit for four weeks during COVID-19 pandemic. This study reviews our experience; focusing on causes of stress and anxiety, and how they were managed. The lessons learnt could be used as a framework for pre-emptive me-asures during future challenges. MATERIAL AND METHODS: Orthopaedic registrars were divided into two groups. Seven trainees (Redeployed group) moved to ITU for four weeks to support the critical care team. The other group (Retained group) of eight registrars continued to cover orthopaedic rota. A survey was done for anxiety levels comparing the two groups at three time points during these four weeks. RESULTS: Anxiety and stress in the ITU-redeployed group was comparatively less than the continuing group as time progressed during the redeployment. CONCLUSIONS: 1. The disruptive impact of the COVID-19 pandemic has been a source of massive stress and an-xiety for health care workers. 2. Our experience shows that stress is controllable with the correct strategies. 3. The main points are early identification of vulnerable groups, proper induction, active involvement, adequate explanation, appreciation, good communication, and available psychological support whenever needed. 4. These are essential to maintain a resilient workforce against upcoming waves of COVID-19.

Trauma surgery at a designated COVID-19-free site during the pandemic: a safe model and a possible way to restart routine elective surgery.

AIMS: Elective operating was halted during the COVID-19 pandemic to increase the capacity to provide care to an unprecedented volume of critically unwell patients. During the pandemic, the orthopaedic department at the Aneurin Bevan University Health Board restructured the trauma service, relocating semi-urgent ambulatory trauma operating to the isolated clean elective centre (St. Woolos' Hospital) from the main hospital receiving COVID-19 patients (Royal Gwent Hospital). This study presents our experience of providing semi-urgent trauma care in a COVID-19-free surgical unit as a safe way to treat trauma patients during the pandemic and a potential model for restarting an elective orthopaedic service. METHODS: All patients undergoing surgery during the COVID-19 pandemic at the orthopaedic surgical unit (OSU) in St. Woolos' Hospital from 23 March 2020 to 24 April 2020 were included. All patients that were operated on had a telephone follow-up two weeks after surgery to assess if they had experienced COVID-19 symptoms or had been tested for COVID-19. The nature of admission, operative details, and patient demographics were obtained from the health board's electronic record. Staff were assessed for sickness, self-isolation, and COVID-19 status. RESULTS: A total of 58 surgical procedures were undertaken at the OSU during the study period; 93% (n = 54) of patients completed the telephone follow-up. Open reduction and internal fixation of ankle and wrist fractures were the most common procedures. None of the patients nor members of their households had developed symptoms suggestive of COVID-19 or required testing. No staff members reported sick days or were advised by occupational health to undergo viral testing. CONCLUSION: This study provides optimism that orthopaedic patients planned for surgery can be protected from COVID-19 nosocomial transmission at separate COVID-19-free sites.Cite this article: Bone Joint Open 2020;1-6:302-308.

Targeting SARS-CoV-2 spike protein of COVID-19 with naturally occurring phytochemicals: an in silico study for drug development.

Spike glycoprotein, a class I fusion protein harboring the surface of SARS-CoV-2 (SARS-CoV-2S), plays a seminal role in the viral infection starting from recognition of the host cell surface receptor, attachment to the fusion of the viral envelope with the host cells. Spike glycoprotein engages host Angiotensin-converting enzyme 2 (ACE2) receptors for entry into host cells, where the receptor recognition and attachment of spike glycoprotein to the ACE2 receptors is a prerequisite step and key determinant of the host cell and tissue tropism. Binding of spike glycoprotein to the ACE2 receptor triggers a cascade of structural transitions, including transition from a metastable pre-fusion to a post-fusion form, thereby allowing membrane fusion and internalization of the virus. From ancient times people have relied on naturally occurring substances like phytochemicals to fight against diseases and infection. Among these phytochemicals, flavonoids and non-flavonoids have been the active sources of different anti-microbial agents. We performed molecular docking studies using 10 potential naturally occurring compounds (flavonoids/non-flavonoids) against the SARS-CoV-2 spike protein and compared their affinity with an FDA approved repurposed drug hydroxychloroquine (HCQ). Further, our molecular dynamics (MD) simulation and energy landscape studies with fisetin, quercetin, and kamferol revealed that these molecules bind with the hACE2-S complex with low binding free energy. The study provided an indication that these molecules might have the potential to perturb the binding of hACE2-S complex. In addition, ADME analysis also suggested that these molecules consist of drug-likeness property, which may be further explored as anti-SARS-CoV-2 agents. Communicated by Ramaswamy H. Sarma.