Role of Glycoprotein Hemagglutinin-Esterase in COVID-19 Pathophysiology?

Molecular identification of neuraminidase gene mutations in influenza A/H1N1 and A/H3N2 isolates of Mazandaran province, north of Iran

OBJECTIVES

The neuraminidase (NA) mutations causing resistance to NA inhibitors (NAIs) mostly compromise the fitness of influenza viruses. Considering the importance of these mutations, constant monitoring of the effectiveness of available drugs is critical. This study aimed to identify NA mutations in the influenza A/H1N1 and A/H3N2 subtypes in the samples of Mazandaran, Iran from 2016 to 2020.

METHODS

In this cross-sectional study, 20 influenza A/H1N1 and 20 influenza A/H3N2 samples were included in the study. After design of appropriate primers for NA gene, all samples subjected to RT-PCR and electrophoresis. Then the PCR product was sequenced to determine the mutations.

RESULTS

In the present study, no oseltamivir resistance-related mutations were detected. Still, NA gene showed variations compared to the vaccine strains. In A/H1N1, a total of 43 mutations were detected. Similarly, in A/H3N2, a total of 66 mutations were observed. In all isolates of H1N1, N200S, N248D and I321V mutations were detected in the antigenic site of NA protein, which can affect vaccine incompatibility and virus escape from the host's immune system. Also, H150R mutation was observed in the NA active site of H3N2, which is the cause of agglutination by NA protein. Also, S245N mutation was identified as a new N-Glycosylation site of H3N2 subtype.

CONCLUSIONS

The study of NA gene sequences revealed no oseltamivir resistance mutations. In H1N1 isolates, ca. 97% identities and in the H3N2 subtype, 96% identities were observed compared to reference isolate of 2009, which indicates the importance of constant monitoring of the emergence of the drug resistance mutations.

SARS-CoV-2 mechanisms of cell tropism in various organs considering host factors

A critical step in the drug design for SARS-CoV-2 is to discover its molecular targets. This study comprehensively reviewed the molecular mechanisms of SARS-CoV-2, exploring host cell tropism and interaction targets crucial for cell entry. The findings revealed that beyond ACE2 as the primary entry receptor, alternative receptors, co-receptors, and several proteases such as TMPRSS2, Furin, Cathepsin L, and ADAM play critical roles in virus entry and subsequent pathogenesis. Additionally, SARS-CoV-2 displays tropism in various human organs due to its diverse receptors. This review delves into the intricate details of receptors, host proteases, and the involvement of each organ. Polymorphisms in the ACE2 receptor and mutations in the spike or its RBD region contribute to the emergence of variants like Alpha, Beta, Gamma, Delta, and Omicron, impacting the pathogenicity of SARS-CoV-2. The challenge posed by mutations raises questions about the effectiveness of existing vaccines and drugs, necessitating consideration for updates in their formulations. In the urgency of these critical situations, repurposed drugs such as Camostat Mesylate and Nafamostat Mesylate emerge as viable pharmaceutical options. Numerous drugs are involved in inhibiting receptors and host factors crucial for SARS-CoV-2 entry, with most discussed in this review. In conclusion, this study may provide valuable insights to inform decisions in therapeutic approaches.

Association between COVID-19 Diagnosis and Coronary Artery Thrombosis: A Narrative Review

Coronavirus disease 2019 is characterized by its severe respiratory effects. Data early on indicated an increased risk of mortality in patients with cardiovascular comorbidities. Early reports highlighted the multisystem inflammatory syndrome, cytokine storm, and thromboembolic events as part of the disease processes. The aim of this review is to assess the association between COVID-19 and its thrombotic complications, specifically related to the cardiovascular system. The role of neutrophil extracellular traps (NETs) is explored in the pathogenesis of the disease. The structure and anatomy of the virus are pivotal to its virulence in comparison to other α and β Coronaviridae (HCoV-229E, HCoV-OC43, HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1). In particular, the host interaction and response may explain the variability of severity in patients. Angio tensin-converting enzyme 2 (ACE2) activation may be implicated in the cardiovascular and throm bogenic potential of the disease. The virus may also have direct effects on the endothelial lining affecting hemostasis and resulting in thrombosis through several mechanisms. Dipyridamole may have a therapeutic benefit in NET suppression. Therapeutic avenues should be concentrated on the different pathophysiological steps involving the virus and the host.

Association between ABO blood groups and rhesus antigen and susceptibility to COVID-19 in the Yazd hospital

Blood group antigens are one of the most important antigens in humans that have an impact on susceptibility to disease and may be used as a prognosis factor in different diseases such as COVID-19. The study aimed to investigate the relationship between ABO blood groups and Rhesus antigen and susceptibility to COVID-19. The clinical data of 398 subjects were used in the investigation collected from 148 cases vs. 250 controls. This information was obtained from Shahid Sadoughi Hospital of Yazd (IRAN) University. Blood groups and outcomes were assessed using statistical tests for four populations: COV + vs. COV− and COV +/deceased vs. COV +/live. Out of a total of 148 COVID-19 patients, 80 (54/1%) were male, 68 (45/9%) were female. Among these patients, 33 (22/6%) had type A+, 44 (30/1%) had type B+, 13 (8/9%) had type AB+, and 36 (24/7%) had type O+. On the other hand, out of 148 patients, 126 (86/3%) had positive blood types, and 20 (13/7%) had negative blood types. As a result, no significant difference was found in the relationship between ABO blood groups and RH type and susceptibility to COVID-19 (p-value = 0.392 and p-value = 0.847, respectively). Other data showed a significant difference between patients group with other parameters such as age (p-value<0.001) and gender (p-value<0.001). Although in this study there was no association between blood type and RH type with COVID-19, findings of the association between age and gender can confirm the results of previous studies.