Broad-spectrum mono- and combinational drug therapies for global viral pandemic preparedness

Broadly effective antiviral therapies must be developed to be ready for clinical trials, which should begin soon after the emergence of new life-threatening viruses. Here, we pave the way towards this goal by analyzing conserved druggable virus-host interactions, mechanisms of action and immunomodulatory properties of broad-spectrum antivirals (BSAs), routes of BSA delivery, and BSA interactions with other antivirals. Based on the analysis we developed scoring systems, which allowed us to predict novel BSAs and BSA-containing drug combinations (BCCs). Thus, we have developed a new strategy to broaden the spectrum of BSA indications and predict novel mono- and combinational therapies that can help better prepare for imminent future viral outbreaks.

SARS-CoV-2 and the Host Cell: A Tale of Interactions

The ability of a virus to spread between individuals, its replication capacity and the clinical course of the infection are macroscopic consequences of a multifaceted molecular interaction of viral components with the host cell. The heavy impact of COVID-19 on the world population, economics and sanitary systems calls for therapeutic and prophylactic solutions that require a deep characterization of the interactions occurring between virus and host cells. Unveiling how SARS-CoV-2 engages with host factors throughout its life cycle is therefore fundamental to understand the pathogenic mechanisms underlying the viral infection and to design antiviral therapies and prophylactic strategies. Two years into the SARS-CoV-2 pandemic, this review provides an overview of the interplay between SARS-CoV-2 and the host cell, with focus on the machinery and compartments pivotal for virus replication and the antiviral cellular response. Starting with the interaction with the cell surface, following the virus replicative cycle through the characterization of the entry pathways, the survival and replication in the cytoplasm, to the mechanisms of egress from the infected cell, this review unravels the complex network of interactions between SARS-CoV-2 and the host cell, highlighting the knowledge that has the potential to set the basis for the development of innovative antiviral strategies.

Animal Model of Severe Fever With Thrombocytopenia Syndrome Virus Infection

Severe fever with thrombocytopenia syndrome (SFTS), an emerging life-threatening infectious disease caused by SFTS bunyavirus (SFTSV; genus Bandavirus, family Phenuiviridae, order Bunyavirales), has been a significant medical problem. Currently, there are no licensed vaccines or specific therapeutic agents available and the viral pathogenesis remains largely unclear. Developing appropriate animal models capable of recapitulating SFTSV infection in humans is crucial for both the study of the viral pathogenic processes and the development of treatment and prevention strategies. Here, we review the current progress in animal models for SFTSV infection by summarizing susceptibility of various potential animal models to SFTSV challenge and the clinical manifestations and histopathological changes in these models. Together with exemplification of studies on SFTSV molecular mechanisms, vaccine candidates, and antiviral drugs, in which animal infection models are utilized, the strengths and limitations of the existing SFTSV animal models and some important directions for future research are also discussed. Further exploration and optimization of SFTSV animal models and the corresponding experimental methods will be undoubtedly valuable for elucidating the viral infection and pathogenesis and evaluating vaccines and antiviral therapies.

Comparing Outcomes of Two Antiviral Therapy Combinations among COVID-19 Patients

Several therapeutic regimens for COVID-19 have been studied, such as combination antiviral therapies. We aimed to compare outcome of two types of combination therapies atazanavir/ritonavir (ATV/r) or lopinavir/ritonavir (LPV/r) plus hydroxychloroquine among COVID-19 patients. 108 patients with moderate and severe forms of COVID-19 were divided into two groups (each group 54 patients). One group received ATV/r plus hydroxychloroquine, and the other group received hydroxychloroquine plus LPV/r. Then, both groups were evaluated and compared for clinical symptoms, recovery rates, and complications of treatment regimens. Our findings showed a significant increase in bilirubin in ATV/r-receiving group compared to LPV/r receivers. There was also a significant increase in arrhythmias in the LPV/r group compared to the ATV/r group during treatment. Other findings including length of hospital stay, outcome, and treatment complications were not statistically significant. There is no significant difference between protease inhibitor drugs including ATV/r and LPV/r in the treatment of COVID-19 regarding clinical outcomes. However, some side effects such as hyperbilirubinemia and arrhythmia were significantly different by application of atazanavir or lopinavir.

Therapeutic Management of COVID-19 Patients

Severe Acute Respiratory Syndrome Coronavirus 2 (SARSCov-2) or COVID-19 is a pandemic that appeared in December 2019 in China and which is an RNA virus. It gave rise to a major health crisis at the start of 2020, with numerous hospitalizations. It was quickly important to understand the pathophysiology of this viral attack on the human body in order to be able to develop treatment. However, there is no vaccine or effective therapeutic agent against SARS-CoV-2. Most of the therapeutic strategies used to deal with this virus come from the work of previous epidemics of SARS, and other influenza viruses, such as antiviral therapies (chloroquine, hydroxychloroquine), adjuvant therapies by combining antivirals with drugs. Antibiotics or immunostimulants (vitamins C, Dm and Zinc, etc,) and several other therapies to be used depending on the region.

Bioinformatic Evaluation of the miRNAs Targeting ACE2 Gene in COVID-19

Introduction: Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which began in late 2019 in Wuhan, China, has become a global epidemic. Angiotensin 2 converting enzyme (ACE2) acts as a receptor for host function to cause acute coronavirus 2 acute respiratory syndrome (SARS-CoV-2). ACE2 is abundantly expressed in different cells of different human organs. In human physiology, ACE2 is a major player in the renin-angiotensin-aldosterone (RAAS) system by degrading angiotensin II. Many factors have been associated with altered ACE2 expression and the severity and progression of COVID-19, including microRNAs that may be effective in it. Identifying pathological changes due to SARS-CoV-2 infection is important because it has major implications for understanding the pathophysiology of COVID-19 and developing evidence-based treatment strategies. Currently, many intervention strategies are being explored in ongoing clinical trials. Objective: The aim of this study is to use bioinformatics databases to find potential antiviral therapies against SARS-CoV-2 through host microRNAs (miRNAs) that can reduce viral gene expression to inhibit virus entry and replication. Methods: Using different algorithms in TargetScan, DIANA, ENCORI and miRWalk databases, the potential microRNAs were identified that target ACE2. Then, a score table was prepared from the candidate microRNAs, based on the affinity of the seed region of microRNAs and the 3`-UTR region of the ACE2 gene. Finally, microRNAs with higher scores were chosen as candidates for practical analysis. Results: The results of Bioinformatical analysis showed that Has-miR-200c-3p, Has-miR-29a, Has-miR-29c, and Has-miR-942 are most likely to inhibit ACE2. These microRNAs are the most potent factors that might be affected on ACE2 during virulence. Conclusion: It seems that ACE2 is under the control of the miR-200c-3p and plays a crucial role in the pathophysiology process. Therefore, this microRNA can be considered as a suitable new candidate for experimental evaluation.

Current strategies in diagnostics and therapeutics against novel coronavirus disease (COVID-19)

The epidemic of COVID-19 spread quickly through China and engulfed all of the countries across the globe. Several advances have been made in understanding the novel coronavirus’s pathophysiology and in the development of newer diagnostics with pinpoint accuracy. Several newer therapeutic methods have either been accepted or are awaiting acceptance. In many countries, vaccination programs have been rolled out. Despite all these efforts, coronavirus still exists, though with lesser propensity. Multiple new forms of the novel coronavirus unexpectedly appeared in various areas of the world, undermining previously existing diagnosis and care protocols. This article highlights our understanding of the novel coronavirus’s symptoms in brief, pathogenesis, diagnostics, and therapeutic strategies to contain COVID-19. The clinical findings, including serological, radiological, and other advanced diagnostic strategies, contributed much to control the disease. To date, supportive interventions have been used in tandem with potent antiviral therapies such as remdesivir, lopinavir/ritonavir, or corticosteroids with a level of trust in the care of COVID-19 patients. However, in several areas of the world, vaccination initiatives took place; the vaccines’ safety and efficacy to control the outbreak is yet to be identified. This review concludes that improvement in therapies and diagnostics for COVID-19 must continually be explored as new variants constantly emerge.

Rotavirus Interactions With Host Intestinal Epithelial Cells

Rotavirus (RV) is the foremost enteric pathogen associated with severe diarrheal illness in young children (<5years) and animals worldwide. RV primarily infects mature enterocytes in the intestinal epithelium causing villus atrophy, enhanced epithelial cell turnover and apoptosis. Intestinal epithelial cells (IECs) being the first physical barrier against RV infection employs a range of innate immune strategies to counteract RVs invasion, including mucus production, toll-like receptor signaling and cytokine/chemokine production. Conversely, RVs have evolved numerous mechanisms to escape/subvert host immunity, seizing translation machinery of the host for effective replication and transmission. RV cell entry process involve penetration through the outer mucus layer, interaction with cell surface molecules and intestinal microbiota before reaching the IECs. For successful cell attachment and entry, RVs use sialic acid, histo-blood group antigens, heat shock cognate protein 70 and cell-surface integrins as attachment factors and/or (co)-receptors. In this review, a comprehensive summary of the existing knowledge of mechanisms underlying RV-IECs interactions, including the role of gut microbiota, during RV infection is presented. Understanding these mechanisms is imperative for developing efficacious strategies to control RV infections, including development of antiviral therapies and vaccines that target specific immune system antagonists within IECs.

APOBEC-mediated Editing of SARS-CoV-2 Genomic RNA Impacts Viral Replication and Fitness

During COVID-19 pandemic, mutations of SARS-CoV-2 produce new strains that can be more virulent and evade vaccines. Viral RNA mutations can arise from misincorporation by RNA-polymerases and modification by host factors. Recent SARS-CoV-2 sequence analyses showed a strong bias toward C-to-U mutation, suggesting that host APOBEC cytosine deaminases with immune functions may cause the mutation. We report the experimental evidence demonstrating that APOBEC3A and APOBEC1 can efficiently edit SARS-CoV-2 RNA to produce C-to-U mutation at specific sites. However, APOBEC-editing does not inhibit the viral RNA accumulation in cells. Instead, APOBEC3A-editing of SARS-CoV-2 promotes viral replication/propagation, suggesting that SARS-CoV-2 utilizes the APOBEC-mediated mutations for fitness and evolution. Unlike the unpredictability of random mutations, this study has significant implications in predicting the potential mutations based on the UC/AC motifs and surrounding RNA structures, thus offering a basis for guiding future antiviral therapies and vaccines against the escape mutants.