Human interaction targets of SARS-COV-2 spike protein: A systematic review

Evaluation of angiotensin converting enzyme 2 (ACE2), angiotensin II (Ang II), miR-141-3p, and miR-421 levels in SARS-CoV-2 patients: a case-control study

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious virus that uses angiotensin converting enzyme 2 (ACE2), a pivotal member of the renin-angiotensin system (RAS), as its cell-entry receptor. Another member of the RAS, angiotensin II (Ang II), is the major biologically active component in this system. There is growing evidence suggesting that serum miRNAs could serve as prognostic biomarkers for SARS-CoV-2 infection and regulate ACE2 expression. Therefore, the aim of this study is to evaluate the changes in the serum levels of sACE2 and Ang II, as well as the expression level of miR-141-3p and miR-421 in SARS-CoV-2 positive and negative subjects.

METHODS

In the present study, the serum levels of sACE2 and Ang II were measured in 94 SARS-CoV-2 positive patients and 94 SARS-CoV-2 negative subjects with some symptoms similar to those of SARS-CoV-2 positive patients using the ELISA method. In addition, the expression level of miR-141-3p and miR-421 as ACE2 regulators and biomarkers was evaluated using quantitative real-time PCR (qRT-PCR) method.

RESULTS

The mean serum sACE2 concentration in the SARS-CoV-2-positive group was 3.268 ± 0.410 ng/ml, whereas in the SARS-CoV-2 negative group, it was 3.564 ± 0.437 ng/ml. Additionally, the mean serum Ang II level in the SARS-CoV-2 positive and negative groups were 60.67 ± 6.192 ng/L and 67.97 ± 6.837 ng/L, respectively. However, there was no significant difference in the serum levels of sACE2 (P value: 0.516) and Ang II (P value: 0.134) between the SARS-CoV-2 positive and negative groups. Meanwhile, our findings indicated that the expression levels of miR-141-3p and miR-421 in SARS-CoV-2 positive group were significantly lower and higher than SARS-CoV-2 negative group, respectively (P value < 0.001).

CONCLUSIONS

Taken together, the results of this study showed that the serum levels of sACE2 and Ang II in SARS-CoV-2 positive and negative subjects were not significantly different, but the expression levels of miR-141-3p and miR-421 were altered in SARS-CoV-2 positive patients which need more investigation to be used as biomarkers for COVID-19 diagnosis.

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.

The role of HLA genetic variants in COVID-19 susceptibility, severity, and mortality: A global review

BACKGROUND

The COVID-19 pandemic has had a profound global impact, with variations in susceptibility, severity, and mortality rates across different regions. While many factors can contribute to the spread and impact of the disease, specifically human leukocyte antigen (HLA) genetic variants have emerged as potential contributors to COVID-19 outcomes.

METHODS

In this comprehensive narrative review, we conducted a thorough literature search to identify relevant studies investigating the association between HLA genetic variants and COVID-19 outcomes. Additionally, we analyzed allelic frequency data from diverse populations to assess differences in COVID-19 incidence and severity.

RESULTS

Our review provides insights into the immunological mechanisms involving HLA-mediated responses to COVID-19 and highlights potential research directions and therapeutic interventions. We found evidence suggesting that certain HLA alleles, such as HLA-A02, may confer a lower risk of COVID-19, while others, like HLA-C04, may increase the risk of severe symptoms and mortality. Furthermore, our analysis of allele frequency distributions revealed significant variations among different populations.

CONCLUSION

Considering host genetic variations, particularly HLA genetic variants, is crucial for understanding COVID-19 susceptibility and severity. These findings have implications for personalized treatment and interventions based on an individual's genetic profile. However, further research is needed to unravel the precise mechanisms underlying the observed associations and explore the potential for targeted therapies or preventive measures based on HLA genetic variants.

The Role of Disordered Regions in Orchestrating the Properties of Multidomain Proteins: The SARS-CoV-2 Nucleocapsid Protein and Its Interaction with Enoxaparin

Novel and efficient strategies need to be developed to interfere with the SARS-CoV-2 virus. One of the most promising pharmaceutical targets is the nucleocapsid protein (N), responsible for genomic RNA packaging. N is composed of two folded domains and three intrinsically disordered regions (IDRs). The globular RNA binding domain (NTD) and the tethered IDRs are rich in positively charged residues. The study of the interaction of N with polyanions can thus help to elucidate one of the key driving forces responsible for its function, i.e., electrostatics. Heparin, one of the most negatively charged natural polyanions, has been used to contrast serious cases of COVID-19 infection, and we decided to study its interaction with N at the molecular level. We focused on the NTR construct, which comprises the NTD and two flanking IDRs, and on the NTD construct in isolation. We characterized this interaction using different nuclear magnetic resonance approaches and isothermal titration calorimetry. With these tools, we were able to identify an extended surface of NTD involved in the interaction. Moreover, we assessed the importance of the IDRs in increasing the affinity for heparin, highlighting how different tracts of these flexible regions modulate the interaction.