Comprehensive deep mutational scanning reveals the pH induced stability and binding differences between SARS-CoV-2 spike RBD and human ACE2.

The SARS-CoV-2 spike (S) glycoprotein with its mobile receptor-binding domain (RBD), binds to the human ACE2 receptor and thus facilitates virus entry through low-pH-endosomal pathways. The high degree of SARS-CoV-2 mutability has raised concern among scientists and medical professionals because it created doubt about the effectiveness of drugs and vaccinations designed specifically for COVID-19. In this study, we used computational saturation mutagenesis approach, including structure-based free energy calculations to analyse the effects of the missense mutations on the SARS-CoV-2 S-RBD stability and the S-RBD binding affinity with ACE2 at three different pH (pH 4.5, pH 6.5, and pH 7.4). A total of 3705 mutations in the S-RBD protein were analyzed, and we discovered that most of these mutations destabilize the RBD protein. Specifically, residues G404, G431, G447, A475, and G526 were important for RBD protein stability. In addition, RBD residues Y449, Y489, Y495, Q498, and N487 were critical for the RBD-ACE2 interaction. Next, we found that the distribution of the mean stability changes and mean binding energy changes of RBD due to mutations at both serological and endosomal pH correlated well, indicating the similar effects of mutations. Overall, this computational analysis is useful for understanding the effects of missense mutations in SARS-CoV-2 pathogenesis at different pH.Communicated by Ramaswamy H. Sarma.

In silico identification of microRNAs targeting the PPARα/γ: promising therapeutics for SARS-CoV­2 infection.

The SARS-CoV-2 lifecycle is dependent on the host metabolism machinery. It upregulates the PPARα and PPARγ genes in lipid metabolism, which supports the essential viral replication complex including lipid rafts and palmitoylation of viral protein. The use of PPAR ligands in SARS-CoV-2 infection may have positive effects by preventing cytokine storm and the ensuing inflammatory cascade. The inhibition of PPARα and PPARγ genes may alter the metabolism and may disrupt the lifecycle of SARS-CoV-2 and COVID-19 progression. In the present work, we have identified possible miRNAs targeting PPARα and PPARγ in search of modulators of PPARα and PPARγ genes expression. The identified miRNAs could possibly be viewed as new therapeutic targets against COVID-19 infection.

Energetic and frustration analysis of SARS-CoV-2 nucleocapsid protein mutations.

The ongoing COVID-19 spreads worldwide with the ability to evolve in diverse human populations. The nucleocapsid (N) protein is one of the mutational hotspots in the SARS-CoV-2 genome. The N protein is an abundant RNA-binding protein critical for viral genome packaging. It comprises two large domains including the N-terminal domain (NTD) and the C-terminal domain (CTD) linked by the centrally located linker region. Mutations in N protein have been reported to increase the severity of disease by modulating viral transmissibility, replication efficiency as well as virulence properties of the virus in different parts of the world. To study the effect of N protein missense mutations on protein stability, function, and pathogenicity, we analyzed 228 mutations from each domain of N protein. Further, we have studied the effect of mutations on local residual frustration changes in N protein. Out of 228 mutations, 11 mutations were predicted to be deleterious and destabilized. Among these mutations, R32C, R191C, and R203 M mutations fall into disordered regions and show significant change in frustration state. Overall, this work reveals that by altering the energetics and residual frustration, N protein mutations might affect the stability, function, and pathogenicity of the SARS-CoV-2.

Development and validation of a predictive scoring system for in-hospital mortality in COVID-19 Egyptian patients: a retrospective study.

SARS-CoV-2 virus has rapidly spread worldwide since December 2019, causing COVID-19 disease. In-hospital mortality is a common indicator for evaluating treatment outcomes. Therefore, the developing and validating a simple score system from observational data could assist in modulating the management procedures. A retrospective cohort study included all data records of patients with positive PCR for SARS-CoV-2. The factors that associated with mortality were analyzed, then allocation of potential predictors of mortality was executed using different logistic regression modeling, subsequently scoring system was developed from the most weighted predictors. The mortality rate of patients with COVID-19 pneumonia was 28.5% and 28.74%, respectively. The most significant factors that affected in-hospital mortality were old age (> 60 years), delay in hospital admission (> 4 days), high neutrophil/lymphocyte ratio "NLR" (> 3); higher computed tomography severity score; and CT-SS (> 20), in addition to using remdesivir and tocilizumab in the treatment protocol (P < 0.001 for all). The validity of the newly performed score was significant; the AUC was 85%, P < 0.001, and its prognostic utility was good; the AUC was 75%, P < 0.001. The prognostic utility of newly developed score system (EGY.Score) was excellent and could be used to adjust the treatment strategy of highly at-risk patients with COVID-19 pneumonia.

In silico evaluation of the inhibitory potential of nucleocapsid inhibitors of SARS-CoV-2: a binding and energetic perspective.

The COVID-19 outbreak brought on by the SARS-CoV-2 virus continued to infect a sizable population worldwide. The SARS-CoV-2 nucleocapsid (N) protein is the most conserved RNA-binding structural protein and is a desirable target because of its involvement in viral transcription and replication. Based on this aspect, this study focused to repurpose antiviral compounds approved or in development for treating COVID-19. The inhibitors chosen are either FDA-approved or are currently being studied in clinical trials against COVID-19. Initially, they were designed to target stress granules and other RNA biology. We have utilized structure-based molecular docking and all-atom molecular dynamics (MD) simulation approach to investigate in detail the binding energy and binding modes of the different anti-N inhibitors to N protein. The result showed that five drugs including Silmitasterib, Ninetanidinb, Ternatin, Luteolin, Fedratinib, PJ34, and Zotatafin were found interacting with RNA binding sites as well as to predicted protein interface with higher binding energy. Overall, drug binding increases the stability of the complex with maximum stability found in the order, Silmitasertib > PJ34 > Zotatatafin. In addition, the frustration changes due to drug binding brings a decrease in local frustration and this decrease is mainly observed in α-helix, ß3, ß5, and ß6 strands and are important for drug binding. Our in-silico data suggest that an effective interaction occurs for some of the tested drugs and prompt their further validation to reduce the rapid outspreading of SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

SARS-CoV-2 origins: zoonotic Rhinolophus vs contemporary models.

The question of the origin of coronavirus spread like wildfire ever since it wreaked havoc among humankind, and ever since the scientific community has worked tirelessly to trace the history of the virus. In this review, we have tried to compile relevant literature pertaining to the different theories of origin of SARS-CoV-2, hopefully without any bias, and we strongly support the zoonotic origin of the infamous SARS-CoV-2 in bats and its transfer to human beings through the most probable evolutionary hosts, pangolins and minks. We also support the contemporary 'Circulation Model' that simply mirrors the concept of evolution to explain the origin of the virus which, the authors believe, is the most rational school of thought. The most recent variant of SARS-CoV-2, Omicron, has been taken as an example to clarify the concept. We recommend the community to refer to this model for further understanding and delving deep into this mystery of the origin of SARS-CoV-2.

Awareness, Knowledge, and Perceptions of COVID-19 Precautions Among Employees of Al-Imam Abdulrahman Al Faisal Hospital in Riyadh, KSA.

Background The global pandemic of coronavirus disease-19 (COVID-19) was announced by the World Health Organization (WHO) in early 2020. The consequences of the pandemic were vast, where healthcare systems, education, and the economy of many countries were greatly affected. As such, extraordinary precautions and measures were implemented to the public as well as to the healthcare systems in order to counter the spread of the disease. However, the success of these measures depends largely on the individual's adherence to them as well as their awareness about COVID-19. Indeed, healthcare workers and their non-medical co-workers play a crucial role in that, as they are considered the front line in fighting the infection. Objectives To assess the knowledge, awareness and perceptions of the healthcare workers (HCWs) regarding COVID-19 in Al-Imam Abdulrahman Al Faisal Hospital in Riyadh, Saudi Arabia. Methods Using a cross-sectional study design, a previously validated questionnaire was used as an online survey to assess the knowledge, awareness and perceptions (KAP) of HCWs regarding COVID-19. The targeted population of this study was all the healthcare workers in Al-Imam Abdulrahman Al Faisal Hospital, including their non-medical co-workers. Results The study included 274 respondents consisting of 53.65% males and 46.45% females with an average age between 30-39 years. The majority of the respondents were paramedics with a percentage of 30.66%. The governmental references were the main source of information regarding COVID-19 for 69% of the respondents. Questions with accurate responses that exceeded 90% were about the COVID-19 complications, transmission, and measures to reduce its transmission. In this study, overall knowledge was significantly associated with the gender of the participants (P=0.01). Conclusion There was a good level of knowledge and perception in health care professionals and co-workers regarding SARS-CoV-2.