Usage of peptidases by SARS-CoV-2 and several human coronaviruses as receptors: A mysterious story

An updated review on pathogenic coronaviruses (CoVs) amid the emergence of SARS-CoV-2 variants: A look into the repercussions and possible solutions

SARS-CoV-2, responsible for COVID-19, shares 79% and 50% of its identity with SARS-CoV-1 and MERS-CoV, respectively. It uses the same main cell attachment and entry receptor as SARS-CoV-1, which is the ACE-2 receptor. However, key residues in the receptor-binding domain of its S-protein seem to give it a stronger affinity for the receptor and a better ability to hide from the host immune system. Like SARS-CoV-1 and MERS-CoV, cytokine storms in critically ill COVID-19 patients cause ARDS, neurological pathology, multiorgan failure, and increased death. Though many issues remain, the global research effort and lessons from SARS-CoV-1 and MERS-CoV are hopeful. The emergence of novel SARS-CoV-2 variants and subvariants raised serious concerns among the scientific community amid the emergence of other viral diseases like monkeypox and Marburg virus, which are major concerns for healthcare settings worldwide. Hence, an updated review on the comparative analysis of various coronaviruses (CoVs) has been developed, which highlights the evolution of CoVs and their repercussions.

Structural and non-structural proteins in SARS-CoV-2: potential aspects to COVID-19 treatment or prevention of progression of related diseases

Coronavirus disease 2019 (COVID-19) is caused by a new member of the Coronaviridae family known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are structural and non-structural proteins (NSPs) in the genome of this virus. S, M, H, and E proteins are structural proteins, and NSPs include accessory and replicase proteins. The structural and NSP components of SARS-CoV-2 play an important role in its infectivity, and some of them may be important in the pathogenesis of chronic diseases, including cancer, coagulation disorders, neurodegenerative disorders, and cardiovascular diseases. The SARS-CoV-2 proteins interact with targets such as angiotensin-converting enzyme 2 (ACE2) receptor. In addition, SARS-CoV-2 can stimulate pathological intracellular signaling pathways by triggering transcription factor hypoxia-inducible factor-1 (HIF-1), neuropilin-1 (NRP-1), CD147, and Eph receptors, which play important roles in the progression of neurodegenerative diseases like Alzheimer's disease, epilepsy, and multiple sclerosis, and multiple cancers such as glioblastoma, lung malignancies, and leukemias. Several compounds such as polyphenols, doxazosin, baricitinib, and ruxolitinib could inhibit these interactions. It has been demonstrated that the SARS-CoV-2 spike protein has a stronger affinity for human ACE2 than the spike protein of SARS-CoV, leading the current study to hypothesize that the newly produced variant Omicron receptor-binding domain (RBD) binds to human ACE2 more strongly than the primary strain. SARS and Middle East respiratory syndrome (MERS) viruses against structural and NSPs have become resistant to previous vaccines. Therefore, the review of recent studies and the performance of current vaccines and their effects on COVID-19 and related diseases has become a vital need to deal with the current conditions. This review examines the potential role of these SARS-CoV-2 proteins in the initiation of chronic diseases, and it is anticipated that these proteins could serve as components of an effective vaccine or treatment for COVID-19 and related diseases. Video Abstract.

Effectiveness of Nutritional Supplements for Attenuating the Side Effects of SARS-CoV-2 Vaccines

Supplementation is known to enhance the immune response and reduce infection. Therefore, the association between immune nutrients and vaccine side effects needs to be investigated. Our aim was to analyze the relationship between vaccination side effects and supplement intake among the Italian population. The study included a questionnaire asking for personal data, anthropometric information, COVID-19 infection and immunity response, and COVID-19 vaccination and supplementation. The survey was conducted from 8 February to 15 June 2022. In the study, 776 respondents were included, aged between 18 and 86 (71.3% females). We observed a statistically significant correlation between supplement consumption and side effects at the end of the vaccination cycle (p = 0.000), which was also confirmed by logistic regression (p = 0.02). Significant associations were observed between supplement intake and side effects of diarrhea and nausea at the end of the vaccination cycle (p = 0.001; p = 0.04, respectively). Significant associations were observed between side effects and omega-3 and mineral supplementation at the start of the vaccination cycle (p = 0.02; p = 0.001, respectively), and between side effects and vitamin supplementation at the end of the vaccination cycle (p = 0.005). In conclusion, our study shows a positive impact of supplementation on vaccination response, increasing host immune defenses, and reducing side effects.

The role of oxidative stress in the pathogenesis of infections with coronaviruses

Coronaviruses can cause serious respiratory tract infections and may also impact other end organs such as the central nervous system, the lung and the heart. The coronavirus disease 2019 (COVID-19) has had a devastating impact on humanity. Understanding the mechanisms that contribute to the pathogenesis of coronavirus infections, will set the foundation for development of new treatments to attenuate the impact of infections with coronaviruses on host cells and tissues. During infection of host cells, coronaviruses trigger an imbalance between increased production of reactive oxygen species (ROS) and reduced antioxidant host responses that leads to increased redox stress. Subsequently, increased redox stress contributes to reduced antiviral host responses and increased virus-induced inflammation and apoptosis that ultimately drive cell and tissue damage and end organ disease. However, there is limited understanding how different coronaviruses including SARS-CoV-2, manipulate cellular machinery that drives redox responses. This review aims to elucidate the redox mechanisms involved in the replication of coronaviruses and associated inflammation, apoptotic pathways, autoimmunity, vascular dysfunction and tissue damage that collectively contribute to multiorgan damage.

Combined effect of traditional Chinese herbal-based formulations Jing Si herbal tea and Jing Si nasal drop inhibits adhesion and transmission of SARS-CoV2 in diabetic SKH-1 mice

Multiple studies show increased severity of SARS-CoV2-infection in patients with comorbidities such as hypertension and diabetes. In this study, we have prepared two herbal-based formulations, a pleiotropic herbal drink (Jin Si Herbal Tea, JHT) and a nasal drop (Jin Si nasal drop, JND), to provide preventive care against SARS-CoV2 infection. The effect of JHT and JND was determined in SARS-CoV2-S-pseudotyped lentivirus-infected bronchial and colorectal cell lines and in SKH-1 mouse models. For preliminary studies, ACE2 receptor abundant bronchial (Calu-3) and colorectal cells (Caco-2) were used to determine the effect of JHT and JND on the host entry of various variants of SARS-CoV2-S-pseudotyped lentivirus. A series of experiments were performed to understand the infection rate in SKH-1 mice (6 weeks old, n = 9), find the effective dosage of JHT and JND, and determine the combination effect of JHT and JND on the entry and adhesion of various variant SARS-CoV2-S-pseudotyped lentiviruses, which included highly transmissible delta and gamma mutants. Furthermore, the effect of combined JHT and JND was determined on diabetes-induced SKH-1 mice against the comorbidity-associated intense viral entry and accumulation. In addition, the effect of combined JHT and JND administration on viral transmission from infected SKH-1 mice to uninfected cage mate mice was determined. The results showed that both JHT and JND were effective in alleviating the viral entry and accumulation in the thorax and the abdominal area. While JHT showed a dose-dependent decrease in the viral load, JND showed early inhibition of viral entry from day 1 of the infection. Combined administration of 48.66 mg of JHT and 20 µL of JND showed rapid reduction in the viral entry and reduced the viral load (97-99%) in the infected mice within 3 days of treatment. Moreover, 16.22 mg of JHT and 20 µL JND reduced the viral infection in STZ-induced diabetic SKH-1 mice. Interestingly, combined JHT and JND also inhibited viral transmission among cage mates. The results, therefore, showed that combined administration of JHT and JND is a novel and an efficient strategy to potentially prevent SARS-CoV2 infection.

Role of Dipeptidyl Peptidase-4 (DPP4) on COVID-19 Physiopathology

DPP4/CD26 is a single-pass transmembrane protein with multiple functions on glycemic control, cell migration and proliferation, and the immune system, among others. It has recently acquired an especial relevance due to the possibility to act as a receptor or co-receptor for SARS-CoV-2, as it has been already demonstrated for other coronaviruses. In this review, we analyze the evidence for the role of DPP4 on COVID-19 risk and clinical outcome, and its contribution to COVID-19 physiopathology. Due to the pathogenetic links between COVID-19 and diabetes mellitus and the hyperinflammatory response, with the hallmark cytokine storm developed very often during the disease, we dive deep into the functions of DPP4 on carbohydrate metabolism and immune system regulation. We show that the broad spectrum of functions regulated by DPP4 is performed both as a protease enzyme, as well as an interacting partner of other molecules on the cell surface. In addition, we provide an update of the DPP4 inhibitors approved by the EMA and/or the FDA, together with the newfangled approval of generic drugs (in 2021 and 2022). This review will also cover the effects of DPP4 inhibitors (i.e., gliptins) on the progression of SARS-CoV-2 infection, showing the role of DPP4 in this disturbing disease.

Whole genome sequencing of SARS-CoV2 strains circulating in Iran during five waves of pandemic

Purpose

Whole genome sequencing of SARS-CoV2 is important to find useful information about the viral lineages, variants of interests and variants of concern. As there are not enough data about the circulating SARS-CoV2 variants in Iran, we sequenced 54 SARS-CoV2 genomes during the 5 waves of pandemic in Iran.

Methods

After viral RNA extraction from clinical samples collected during the COVID-19 pandemic, next generation sequencing was performed using the Nextseq platform. The sequencing data were analyzed and compared with reference sequences.

Results

During the 1st wave, V and L clades were detected. The second wave was recognized by G, GH and GR clades. Circulating clades during the 3rd wave were GH and GR. In the fourth wave GRY (alpha variant), GK (delta variant) and one GH clade (beta variant) were detected. All viruses in the fifth wave were in clade GK (delta variant). There were different mutations in all parts of the genomes but Spike-D614G, NSP12-P323L, N-R203K and N-G204R were the most frequent mutants in these studied viruses.

Conclusions

These findings display the significance of SARS-CoV2 monitoring to help on time detection of possible variants for pandemic control and vaccination plans.

Potential role of viral infections in miscarriage and insights into the underlying molecular mechanisms

Intrauterine viruses can infect the decidua and placenta and cause adverse effects on the fetus during gestation. This review discusses the contribution of various viral infections to miscarriage and the molecular mechanisms by which viruses can cause devastating effects on healthy fetuses and induce miscarriage. Severe acute respiratory syndrome coronavirus 2 as newly emerged coronavirus was considered here, due to the concerns about its role during pregnancy and inducing miscarriage, as well. In this narrative review, an extensive literature search was conducted to find all studies investigating viral infections in miscarriage and their molecular mechanisms published over the past 20 years. The results of various studies investigating the roles of 20 viral infections in miscarriage are presented. Then, the mechanisms of pregnancy loss in viral infections were addressed, including alteration of trophoblast invasion and placental dysfunction, inducing excessive maternal immune response, and inducing apoptosis in the placental tissue. Viruses may cause pregnancy loss through different mechanisms and our knowledge about these mechanisms can be helpful for controlling or preventing viral infections and achieving a successful pregnancy.

Vectorial Release of Human RNA Viruses from Epithelial Cells

Epithelial cells are apico-basolateral polarized cells that line all tubular organs and are often targets for infectious agents. This review focuses on the release of human RNA virus particles from both sides of polarized human cells grown on transwells. Most viruses that infect the mucosa leave their host cells mainly via the apical side while basolateral release is linked to virus propagation within the host. Viruses do this by hijacking the cellular factors involved in polarization and trafficking. Thus, understanding epithelial polarization is essential for a clear understanding of virus pathophysiology.

Structure-function relations of the SARS-CoV-2 spike protein and impact of mutations in the variants of concern

This review covers the main features of the severe acquired respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, its interaction with the main entry receptor, the human angiotensin converting enzyme 2 (ACE2), and the subsequent membrane fusion step. The focus is on the structural organization of these proteins and mechanistic aspects of their interactions that lead to cytoplasmic release of the viral genome. The most potently neutralizing antibodies against SARS-CoV-2 were shown to interfere with the spike/ACE2 interaction. I thus also review the location and the potential impact of mutations in the spike protein observed in the variants of concern that emerged concomitantly with acquired immunity in the population after one year of virus circulation. Understanding how these interactions affect the spike/ACE2 interactions and the subsequent spike-protein-induced membrane fusion reaction is important to stay one step ahead of the virus evolution and develop efficient countermeasures.