Statins Suppress Ebola Virus Infectivity by Interfering with Glycoprotein Processing

Cholesterol: A friend to viruses

Cholesterol is a key life-sustaining molecule which regulates membrane fluidity and serves as a signaling mediator. Cholesterol homeostasis is closely related to various pathological conditions including tumor, obesity, atherosclerosis, Alzheimer's disease and viral infection. Viral infection disrupts host cholesterol homeostasis, facilitating their own survival. Meanwhile, the host cells strive to reduce cholesterol accessibility to limit viral infection. This review focuses on the regulation of cholesterol metabolism and the role of cholesterol in viral infection, specifically providing an overview of cholesterol as a friend to promote viral entry, replication, assembly, release and immune evasion, which might inspire valuable thinking for pathogenesis and intervention of viral infection.

Navigating the Complex Landscape of Ebola Infection Treatment: A Review of Emerging Pharmacological Approaches

In 1976 Ebola revealed itself to the world, marking the beginning of a series of localized outbreaks. However, it was the Ebola outbreak that began in 2013 that incited fear and anxiety around the globe. Since then, our comprehension of the virus has been steadily expanding. Ebola virus (EBOV), belonging to the Orthoebolavirus genus of the Filoviridae family, possesses a non-segmented, negative single-stranded RNA genome comprising seven genes that encode multiple proteins. These proteins collectively orchestrate the intricate process of infecting host cells. It is not possible to view each protein as monofunctional. Instead, they synergistically contribute to the pathogenicity of the virus. Understanding this multifaceted replication cycle is crucial for the development of effective antiviral strategies. Currently, two antibody-based therapeutics have received approval for treating Ebola virus disease (EVD). In 2022, the first evidence-based clinical practice guideline dedicated to specific therapies for EVD was published. Although notable progress has been made in recent years, deaths still occur. Consequently, there is an urgent need to enhance the therapeutic options available to improve the outcomes of the disease. Emerging therapeutics can target viral proteins as direct-acting antivirals or host factors as host-directed antivirals. They both have advantages and disadvantages. One way to bypass some disadvantages is to repurpose already approved drugs for non-EVD indications to treat EVD. This review offers detailed insight into the role of each viral protein in the replication cycle of the virus, as understanding how the virus interacts with host cells is critical to understanding how emerging therapeutics exert their activity. Using this knowledge, this review delves into the intricate mechanisms of action of current and emerging therapeutics.

Host antiviral factors hijack furin to block SARS-CoV-2, ebola virus, and HIV-1 glycoproteins cleavage

Viral envelope glycoproteins are crucial for viral infections. In the process of enveloped viruses budding and release from the producer cells, viral envelope glycoproteins are presented on the viral membrane surface as spikes, promoting the virus's next-round infection of target cells. However, the host cells evolve counteracting mechanisms in the long-term virus-host co-evolutionary processes. For instance, the host cell antiviral factors could potently suppress viral replication by targeting their envelope glycoproteins through multiple channels, including their intracellular synthesis, glycosylation modification, assembly into virions, and binding to target cell receptors. Recently, a group of studies discovered that some host antiviral proteins specifically recognized host proprotein convertase (PC) furin and blocked its cleavage of viral envelope glycoproteins, thus impairing viral infectivity. Here, in this review, we briefly summarize several such host antiviral factors and analyze their roles in reducing furin cleavage of viral envelope glycoproteins, aiming at providing insights for future antiviral studies.

AMFR promotes innate immunity activation and proteasomal degradation of HMGCR in response to influenza virus infection in A549 cells

Differential regulation of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), which is considered the rate-limiting enzyme of the cholesterol biosynthesis pathway, has been reported in case of infection with many viruses. In our study, we have found that influenza virus infection decreases total cellular cholesterol level which is directly related to the downregulation of HMGCR protein. We found that HMGCR is degraded through ubiquitination and proteasomal-mediated pathway upon viral infection. Upregulation of Autocrine Motility Factor Receptor (AMFR), which is an E3-ubiquitin ligase of HMGCR, was also observed. Furthermore, knockdown of AMFR inhibits ubiquitination of HMGCR and also leads to inactivation of the innate immunity components TANK-binding kinase 1 (TBK1) and Interferon regulatory factor 3 (IRF3). Our study is the first to show the role of HMGCR and AMFR in influenza virus infection and reveals that AMFR plays a crucial role in the downregulation of HMGCR and the activation of innate immunity following influenza virus infection.

Outpatient atorvastatin use and severe COVID-19 outcomes: A population-based study

Evidence of the effect of statins on patients with coronavirus disease (2019) COVID-19 is inconsistent. The aim of this study was to evaluate the association between chronic use of statins-both overall and by active ingredient-and severe outcomes of COVID-19 (risk of hospitalization and mortality), progression to severe outcomes, and susceptibility to the virus. We conducted a population-based case-control study with data from electronic records to assess the risk of (1) hospitalization: cases were patients admitted due to COVID-19 and controls were subjects without COVID-19; (2) mortality: cases were hospitalized patients who died due to COVID-19 and controls were subjects without COVID-19; (3) progression: cases were hospitalized COVID-19 subjects and controls were nonhospitalized COVID-19 patients; and (4) susceptibility: cases were patients with COVID-19 (both hospitalized and nonhospitalized) and controls were subjects without COVID-19. We collected data on 2821 hospitalized cases, 26 996 nonhospitalized cases, and 52 318 controls. Chronic use of atorvastatin was associated with a decreased risk of hospitalization (adjusted odds ratios [aOR] = 0.83; 95% confidence interval [CI]: 0.74-0.92) and mortality (aOR = 0.70; 95% CI: 0.53-0.93), attributable in part to a lower risk of susceptibility to the virus (aOR = 0.91; 95% CI: 0.86-0.96). Simvastatin was associated with a reduced risk of mortality (aOR = 0.59; 95% CI: 0.40-0.87). The wide degree of heterogeneity observed in the estimated odds ratios (ORs) of the different statins suggests that there is no class effect. The results of this real-world study suggest that chronic use of atorvastatin (and to a lesser degree, of simvastatin) is associated with a decrease in risk of severe COVID-19 outcomes.

Elucidation of the Cellular Interactome of African Swine Fever Virus Fusion Proteins and Identification of Potential Therapeutic Targets

African swine fever virus (ASFV) encodes more than 150 proteins, most of them of unknown function. We used a high-throughput proteomic analysis to elucidate the interactome of four ASFV proteins, which potentially mediate a critical step of the infection cycle, the fusion and endosomal exit of the virions. Using affinity purification and mass spectrometry, we were able to identify potential interacting partners for those ASFV proteins P34, E199L, MGF360-15R and E248R. Representative molecular pathways for these proteins were intracellular and Golgi vesicle transport, endoplasmic reticulum organization, lipid biosynthesis, and cholesterol metabolism. Rab geranyl geranylation emerged as a significant hit, and also Rab proteins, which are crucial regulators of the endocytic pathway and interactors of both p34 and E199L. Rab proteins co-ordinate a tight regulation of the endocytic pathway that is necessary for ASFV infection. Moreover, several interactors were proteins involved in the molecular exchange at ER membrane contacts. These ASFV fusion proteins shared interacting partners, suggesting potential common functions. Membrane trafficking and lipid metabolism were important categories, as we found significant interactions with several enzymes of the lipid metabolism. These targets were confirmed using specific inhibitors with antiviral effect in cell lines and macrophages.

Statins: Beneficial Effects in Treatment of COVID-19

The recent viral disease COVID-19 has attracted much attention. The disease is caused by SARS-CoV-19 virus which has different variants and mutations. The mortality rate of SARS-CoV-19 is high and efforts to establish proper therapeutic solutions are still ongoing. Inflammation plays a substantial part in the pathogenesis of this disease causing mainly lung tissue destruction and eventually death. Therefore, anti-inflammatory drugs or treatments that can inhibit inflammation are important options. Various inflammatory pathways such as nuclear factor Kappa B (NF-κB), signal transducer of activators of transcription (STAT), nod-like receptor family protein 3 (NLRP), toll-like receptors (TLRs), mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) pathways and mediators, such as interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α), and interferon-γ (INF-γ), cause cell apoptosis, reduce respiratory capacity and oxygen supply, eventually inducing respiratory system failure and death. Statins are well known for controlling hypercholesterolemia and may serve to treat COVID-19 due to their pleiotropic effects among which are anti-inflammatory in nature. In this chapter, the anti-inflammatory effects of statins and their possible beneficial effects in COVID-19 treatment are discussed. Data were collected from experimental and clinical studies in English (1998-October 2022) from Google Scholar, PubMed, Scopus, and the Cochrane Library.

Cholesterol accumulation on dendritic cells reverses chronic hepatitis B virus infection-induced dysfunction

Chronic hepatitis B (CHB) infection remains a serious public health problem worldwide; however, the relationship between cholesterol levels and CHB remains unclear. We isolated peripheral blood mononuclear cells from healthy blood donors and CHB patients to analyze free cholesterol levels, lipid raft formation, and cholesterol metabolism-related pathways. Hepatitis B virus (HBV)-carrier mice were generated and used to confirm changes in cholesterol metabolism and cell-surface lipid raft formation in dendritic cells (DCs) in the context of CHB. Additionally, HBV-carrier mice were immunized with a recombinant HBV vaccine (rHBVvac) combined with lipophilic statins and evaluated for vaccine efficacy against HBV. Serum samples were analyzed for HBsAg, anti-HBs, and alanine aminotransferase levels, and liver samples were evaluated for HBV DNA and RNA and HBcAg. CHB reduced free cholesterol levels and suppressed lipid raft formation on DCs in patients with CHB and HBV-carrier mice, whereas administration of lipophilic statins promoted free cholesterol accumulation and restored lipid rafts on DCs accompanied by an enhanced antigen-presentation ability in vitro and in vivo. Cholesterol accumulation on DCs improved the rHBVvac-mediated elimination of serum HBV DNA and intrahepatic HBV DNA, HBV RNA, and HBcAg and promoted the rHBVvac-mediated generation and polyfunctionality of HBV-specific CD11ahi CD8αlo cells, induction of the development of memory responses against HBV reinfection, and seroconversion from HBsAg to anti-HBs. The results demonstrated the important role of cholesterol levels in DC dysfunction during CHB, suggesting that strategies to increase cholesterol accumulation on DCs might enhance therapeutic vaccine efficacy against HBV and support development toward clinical CHB treatment.

Development of an imaging system for visualization of Ebola virus glycoprotein throughout the viral lifecycle

Ebola virus (EBOV) causes severe EBOV disease (EVD) in humans and non-human primates. Currently, limited countermeasures are available, and the virus must be studied in biosafety level-4 (BSL-4) laboratories. EBOV glycoprotein (GP) is a single transmembrane protein responsible for entry into host cells and is the target of multiple approved drugs. However, the molecular mechanisms underlying the intracellular dynamics of GP during EBOV lifecycle are poorly understood. In this study, we developed a novel GP monitoring system using transcription- and replication-competent virus-like particles (trVLPs) that enables the modeling of the EBOV lifecycle under BSL-2 conditions. We constructed plasmids to generate trVLPs containing the coding sequence of EBOV GP, in which the mucin-like domain (MLD) was replaced with fluorescent proteins. The generated trVLP efficiently replicated over multiple generations was similar to the wild type trVLP. Furthermore, we confirmed that the novel trVLP system enabled real-time visualization of GP throughout the trVLP replication cycle and exhibited intracellular localization similar to that of wild type GP. In summary, this novel monitoring system for GP will enable the characterization of the molecular mechanism of the EBOV lifecycle and can be applied for the development of therapeutics against EVD.

Statin Therapy and the Risk of Viral Infection: A Retrospective Population-Based Cohort Study

Statins exert cholesterol-independent beneficial effects, including immunomodulatory effects. In this study, we attempted to investigate the association between statin therapy and the risk of viral infection. We conducted a retrospective cohort study using data from Taiwan’s National Health Insurance Research Database. We identified patients with hyperlipidemia and divided them into two cohorts: statin users and statin nonusers. A 1:1 propensity score matching was conducted between the two cohorts, and a Cox proportional hazards model was used to evaluate the risk of viral infection. Overall, a total of 20,202 patients were included in each cohort. The median follow-up durations were 4.41 and 6.90 years for statin nonusers and users, respectively. The risk of viral infection was 0.40-fold (95% confidence interval = 0.38–0.41) in statin users than in statin nonusers after adjustment for potential confounders. Statin treatment was associated with a significantly lower risk of viral infection in all age groups older than 18 years in both men and women. Moreover, the risk of viral infection substantially reduced as the duration of statin treatment increased. Our findings suggest that statin therapy is associated with a significantly lower risk of viral infection in patients with hyperlipidemia.

Biological Actions, Implications, and Cautions of Statins Therapy in COVID-19

The Coronavirus Disease 2019 (COVID-19) showed worse prognosis and higher mortality in individuals with obesity. Dyslipidemia is a major link between obesity and COVID-19 severity. Statins as the most common lipid regulating drugs have shown favorable effects in various pathophysiological states. Importantly, accumulating observational studies have suggested that statin use is associated with reduced risk of progressing to severe illness and in-hospital death in COVID-19 patients. Possible explanations underlie these protective impacts include their abilities of reducing cholesterol, suppressing viral entry and replication, anti-inflammation and immunomodulatory effects, as well as anti-thrombosis and anti-oxidative properties. Despite these benefits, statin therapies have side effects that should be considered, such as elevated creatinine kinase, liver enzyme and serum glucose levels, which are already elevated in severe COVID-19. Concerns are also raised whether statins interfere with the efficacy of COVID-19 vaccines. Randomized controlled trials are being conducted worldwide to confirm the values of statin use for COVID-19 treatment. Generally, the results suggest no necessity to discontinue statin use, and no evidence suggesting interference between statins and COVID-19 vaccines. However, concomitant administration of statins and COVID-19 antiviral drug Paxlovid may increase statin exposure and the risk of adverse effects, because most statins are metabolized mainly through CYP3A4 which is potently inhibited by ritonavir, a major component of Paxlovid. Therefore, more clinical/preclinical studies are still warranted to understand the benefits, harms and mechanisms of statin use in the context of COVID-19.

Association of Statins for Primary Prevention of Cardiovascular Diseases With Hospitalization for COVID-19: A Nationwide Matched Population-Based Cohort Study

Background

There is little evidence on the relationship between statin use and the risk of hospitalization attributable to COVID‐19.

Methods and Results

The French National Healthcare Data System database was used to conduct a matched‐cohort study. For each adult aged ≥40 years receiving statins for the primary prevention of cardiovascular diseases, one nonuser was randomly selected and matched for year of birth, sex, residence area, and comorbidities. The association between statin use and hospitalization for COVID‐19 was examined using conditional Cox proportional hazards models, adjusted for baseline characteristics, comorbidities, and long‐term medications. Its association with in‐hospital death from COVID‐19 was also explored. All participants were followed up from February 15, 2020, to June 15, 2020. The matching procedure generated 2 058 249 adults in the statin group and 2 058 249 in the control group, composed of 46.6% of men with a mean age of 68.7 years. Statin users had a 16% lower risk of hospitalization for COVID‐19 than nonusers (adjusted hazard ratio [HR], 0.84; 95% CI, 0.81–0.88). All types of statins were significantly associated with a lower risk of hospitalization, with the adjusted HR ranging from 0.75 for fluvastatin to 0.89 for atorvastatin. Low‐ and moderate‐intensity statins also showed a lower risk compared with nonusers (HR, 0.78 [95% CI, 0.71–0.86] and HR, 0.84 [95% CI, 0.80–0.89], respectively), whereas high‐intensity statins did not (HR, 1.01; 95% CI, 0.86–1.18). We found similar results with in‐hospital death from COVID‐19.

Conclusions

Our findings support that the use of statins for primary prevention is associated with lower risks of hospitalization for COVID‐19 and of in‐hospital death from COVID‐19.

The Impact of Cardiovascular Risk Factors on the Course of COVID-19

Aim of the study: The aim of our review is to indicate and discuss the impact of cardiovascular risk factors, such as obesity, diabetes, lipid profile, hypertension and smoking on the course and mortality of COVID-19 infection. Background: The coronavirus disease 2019 (COVID-19) pandemic is spreading around the world and becoming a major public health crisis. All coronaviruses are known to affect the cardiovascular system. There is a strong correlation between cardiovascular risk factors and severe clinical complications, including death in COVID-19 patients. All the above-mentioned risk factors are widespread and constitute a significant worldwide health problem. Some of them are modifiable and the awareness of their connection with the COVID-19 progress may have a crucial impact on the current and possible upcoming infection. Data collection: We searched for research papers describing the impact of selected cardiovascular risk factors on the course, severity, complications and mortality of COVID-19 infection form PubMed and Google Scholar databases. Using terms, for example: “COVID-19 cardiovascular disease mortality”, “COVID-19 hypertension/diabetes mellitus/obesity/dyslipidemia”, “cardiovascular risk factors COVID-19 mortality” and other related terms listed in each subtitle. The publications were selected according to the time of their publications between January 2020 and December 2021. From the PubMed database we obtain 1552 results. Further studies were sought by manually searching reference lists of the relevant articles. Relevant articles were selected based on their title, abstract or full text. Articles were excluded if they were clearly related to another subject matter or were not published in English. The types of articles are mainly randomized controlled trial and systematic review. An additional criterion used by researchers was co-morbidities and age of patients in study groups. From a review of the publications, 105 of them were selected for this work with all subheadings included. Findings and Results: The intention of this review was to summarize current knowledge about comorbidities and development of COVID-19 infection. We tried to focus on the course and mortality of the abovementioned virus disease in patients with concomitant CV risk factors. Unfortunately, we were unable to assess the quality of data in screened papers and studies we choose because of the heterogenicity of the groups. The conducted studies had different endpoints and included different groups of patients in terms of nationality, age, race and clinical status. We decide to divide the main subjects of the research into separately described subtitles such as obesity, lipid profile, hypertension, diabetes, smoking. We believe that the studies we included and gathered are very interesting and show modern and present-day clinical data and approaches to COVID-19 infection in specific divisions of patients.

Atorvastatin Effectively Inhibits Ancestral and Two Emerging Variants of SARS-CoV-2 in vitro

This article evaluated the in vitro antiviral effect of atorvastatin (ATV) against SARS-CoV-2 and identified the interaction affinity between this compound and two SARS-CoV-2 proteins. The antiviral activity of atorvastatin against this virus was evaluated by three different treatment strategies [(i) pre-post treatment, (ii) pre-infection treatment, and (iii) post-infection treatment] using Vero E6 and Caco-2 cells. The interaction of atorvastatin with RdRp (RNA-dependent RNA polymerase) and 3CL protease (3-chymotrypsin-like protease) was evaluated by molecular docking. The CC50s (half-maximal cytotoxic concentrations) obtained for ATV were 50.3 and 64.5 μM in Vero E6 and Caco-2, respectively. This compound showed antiviral activity against SARS-CoV-2 D614G strain in Vero E6 with median effective concentrations (EC50s) of 15.4, 12.1, and 11.1 μM by pre-post, pre-infection, and post-infection treatments, respectively. ATV also inhibited Delta and Mu variants by pre-post treatment (EC50s of 16.8 and 21.1 μM, respectively). In addition, ATV showed an antiviral effect against the D614G strain independent of the cell line (EC50 of 7.4 μM in Caco-2). The interaction of atorvastatin with SARS-CoV-2 RdRp and 3CL protease yielded a binding affinity of -6.7 kcal/mol and -7.5 kcal/mol, respectively. Our study demonstrated the in vitro antiviral activity of atorvastatin against the ancestral SARS-CoV-2 D614G strain and two emerging variants (Delta and Mu), with an independent effect of the cell line. A favorable binding affinity between ATV and viral proteins by bioinformatics methods was found. Due to the extensive clinical experience of atorvastatin use, it could prove valuable in the treatment of COVID-19.

Role of Lipid Rafts in Pathogen-Host Interaction - A Mini Review

Lipid rafts, also known as microdomains, are important components of cell membranes and are enriched in cholesterol, glycophospholipids and receptors. They are involved in various essential cellular processes, including endocytosis, exocytosis and cellular signaling. Receptors are concentrated at lipid rafts, through which cellular signaling can be transmitted. Pathogens exploit these signaling mechanisms to enter cells, proliferate and egress. However, lipid rafts also play an important role in initiating antimicrobial responses by sensing pathogens via clustered pathogen-sensing receptors and triggering downstream signaling events such as programmed cell death or cytokine production for pathogen clearance. In this review, we discuss how both host and pathogens use lipid rafts and associated proteins in an arms race to survive. Special attention is given to the involvement of the major vault protein, the main constituent of a ribonucleoprotein complex, which is enriched in lipid rafts upon infection with vaccinia virus.

Atorvastatin Efficacy in the Management of Mild to Moderate Hospitalized COVID-19: A Pilot Randomized Triple-blind Placebo- controlled Clinical Trial

BACKGROUND

Statins are first-line lipid-lowering agents with tolerable adverse reactions, low cost, and high availability worldwide. The potent anti-inflammatory, antioxidant, anti-thrombotic and immunomodulatory effects of statins propose them as an option against COVID-19 infection.

OBJECTIVE

In this randomized triple-blind placebo-controlled clinical trial, we have investigated the atorvastatin efficacy in the management of mild to moderate hospitalized COVID-19 patients.

METHODS

In this study, 52 mild to moderate hospitalized COVID-19 patients who fulfilled the inclusion criteria were allocated to the treatment group to receive 40 mg atorvastatin orally once daily for two weeks (n=26) or the placebo group (n=26). Patients' symptoms and laboratory investigations were assessed at baseline and during the follow-up period. We also evaluated the duration of hospitalization and supplemental oxygen therapy as endpoints.

RESULTS

After 14-day of follow-up, the oxygen saturation (SaO2) was significantly higher, and the serum high sensitivity C-reactive protein (hs-CRP) level was lower in the treatment group compared to the placebo group. Moreover, at the end of the followup in the treatment group, the lymphocyte count was higher, and the duration of symptom resolution was shorter but not significant. Additionally, in the treatment group, the length of supplemental oxygen therapy and hospitalization duration were meaningfully shorter. Our results revealed that the mortality rate was almost twice higher in the placebo group compared to the treatment group, without any significant adverse drug reaction.

CONCLUSION

Atorvastatin significantly reduces supplemental oxygen need, hospitalization duration, and serum hs-CRP level in mild to moderate hospitalized COVID-19 patients.

Fluvastatin mitigates SARS-CoV-2 infection in human lung cells

Clinical data of patients suffering from COVID-19 indicates that statin therapy, used to treat hypercholesterolemia, is associated with a better disease outcome. Whether statins directly affect virus replication or influence the clinical outcome through modulation of immune responses is unknown. We therefore investigated the effect of statins on SARS-CoV-2 infection in human lung cells and found that only fluvastatin inhibited low and high pathogenic coronaviruses in vitro and ex vivo in a dose-dependent manner. Quantitative proteomics revealed that fluvastatin and other tested statins modulated the cholesterol synthesis pathway without altering innate antiviral immune responses in infected lung epithelial cells. However, fluvastatin treatment specifically downregulated proteins that modulate protein translation and viral replication. Collectively, these results support the notion that statin therapy poses no additional risk to individuals exposed to SARS-CoV-2 and that fluvastatin has a moderate beneficial effect on SARS-CoV-2 infection of human lung cells.

Identification of potential inhibitors of SARS-CoV-2 S protein-ACE2 interaction by in silico drug repurposing

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new coronavirus discovered that appeared in Wuhan, China, in December 2019, causes COVID-19 disease which have resulted in cases similar to SARS-atypical pneumonia. Worldwide, around 116 million cases and 2.57 million deaths are reported with new cases and increasing mortality every day. To date, there is no specific commercial treatment to control the infection. Repurpose drugs targeting the angiotensin-converting enzyme 2 (ACE2) receptor represents an alternative strategy to block the binding of SARS-CoV-2 protein S and forestall virus adhesion, internalization, and replication in the host cell.

Methods: We performed a rigid molecular docking using the receptor binding domain of the S1 subunit of S protein (RBD _S1)-ACE2 (PDB ID: 6VW1) interaction site and 1,283 drugs FDA approved. The docking score, frequency of the drug in receptor site, and interactions at the binding site residues were used as analyzing criteria.

Results: This research yielded 40 drugs identified as a potential inhibitor of RBD _S1-ACE2 interaction. Among the inhibitors, compounds such as ipratropium, formoterol, and fexofenadine can be found. Specialists employ these drugs as therapies to treat chronic obstructive pulmonary disease, asthma and virtually any respiratory infection.

Conclusions: Our results will serve as the basis for in vitro and in vivo studies to evaluate the potential use of those drugs to generate affordable and convenient therapies to treat COVID-19.

Statin-mediated disruption of Rho GTPase prenylation and activity inhibits respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is a leading cause of severe respiratory tract infections in children. To uncover new antiviral therapies, we developed a live cell-based high content screening approach for rapid identification of RSV inhibitors and characterized five drug classes which inhibit the virus. Among the molecular targets for each hit, there was a strong functional enrichment in lipid metabolic pathways. Modulation of lipid metabolites by statins, a key hit from our screen, decreases the production of infectious virus through a combination of cholesterol and isoprenoid-mediated effects. Notably, RSV infection globally upregulates host protein prenylation, including the prenylation of Rho GTPases. Treatment by statins or perillyl alcohol, a geranylgeranyltransferase inhibitor, reduces infection in vitro. Of the Rho GTPases assayed in our study, a loss in Rac1 activity strongly inhibits the virus through a decrease in F protein surface expression. Our findings provide new insight into the importance of host lipid metabolism to RSV infection and highlight geranylgeranyltransferases as an antiviral target for therapeutic development.

Anti-flavivirus Properties of Lipid-Lowering Drugs

Although Flaviviruses such as dengue (DENV) and zika (ZIKV) virus are important human pathogens, an effective vaccine or antiviral treatment against them is not available. Hence, the search for new strategies to control flavivirus infections is essential. Several studies have shown that the host lipid metabolism could be an antiviral target because cholesterol and other lipids are required during the replicative cycle of different Flaviviridae family members. FDA-approved drugs with hypolipidemic effects could be an alternative for treating flavivirus infections. However, a better understanding of the regulation between host lipid metabolism and signaling pathways triggered during these infections is required. The metabolic pathways related to lipid metabolism modified during DENV and ZIKV infection are analyzed in this review. Additionally, the role of lipid-lowering drugs as safe host-targeted antivirals is discussed.

The role of lovastatin in the attenuation of COVID-19

The mounting evidence regarding the pathogenesis of COVID-19 indicated that the cytokine storm has an axial role in the severity of this disease, which may lead to thrombotic complications, acute respiratory distress syndrome (ARDS), and myocardial damage, among other consequences. It has recently been demonstrated that statins are known to have anti-viral, anti-inflammatory, anti-thrombotic, and immunomodulatory features; however, their advantage has not been evaluated in COVID-19. This study aimed to investigate the protective effects of lovastatin in intensive care unit (ICU) patients with COVID-19. The case-control study consists of 284 ICU patients, which classified into three groups as follows: 1) the patients who no received lovastatin as a control (92 patients), 2) patients received 20 mg per day lovastatin (99 patients), and 3) patients received 40 mg per day lovastatin (93 patients). Each group's demographic and clinical parameters, along with CRP, interleukin (IL)-6, IL-8 levels, and mortality rate, were studied in three-time points. The results showed that there was no statistically significant difference between our study groups in terms of age and sex. (P > 0.05). Besides, in patients, receiving lovastatin the CRP, IL-6, IL-8 levels were significantly decreased from T1 to T3 than to the control group. Our results also showed that the use of lovastatin in COVID-19 patients significantly reduced the length of hospitalization in the ICU compared with the control group. In addition, our results showed that the mortality rate in patients receiving lovastatin was lower when compared to the control group; however, this difference was not statistically significant. Since the cytokine storm is a significant factor in the pathology of SARS-CoV-2, our findings highlighted the potential use of lovastatin to mitigate the inflammatory response induced by SARS-CoV-2 infection.

The Methanolic Extract of Perilla frutescens Robustly Restricts Ebola Virus Glycoprotein-Mediated Entry

Ebola virus (EBOV), one of the most infectious human viruses and a leading cause of viral hemorrhagic fever, imposes a potential public health threat with several recent outbreaks. Despite the difficulties associated with working with this pathogen in biosafety level-4 containment, a protective vaccine and antiviral therapeutic were recently approved. However, the high mortality rate of EBOV infection underscores the necessity to continuously identify novel antiviral strategies to help expand the scope of prophylaxis/therapeutic management against future outbreaks. This includes identifying antiviral agents that target EBOV entry, which could improve the management of EBOV infection. Herein, using EBOV glycoprotein (GP)-pseudotyped particles, we screened a panel of natural medicinal extracts, and identified the methanolic extract of Perilla frutescens (PFME) as a robust inhibitor of EBOV entry. We show that PFME dose-dependently impeded EBOV GP-mediated infection at non-cytotoxic concentrations, and exerted the most significant antiviral activity when both the extract and the pseudoparticles are concurrently present on the host cells. Specifically, we demonstrate that PFME could block viral attachment and neutralize the cell-free viral particles. Our results, therefore, identified PFME as a potent inhibitor of EBOV entry, which merits further evaluation for development as a therapeutic strategy against EBOV infection.

Drug repurposing against SARS-CoV-2 using E-pharmacophore based virtual screening, molecular docking and molecular dynamics with main protease as the target

Since its first report in December 2019 from China, the COVID-19 pandemic caused by the beta-coronavirus SARS-CoV-2 has spread at an alarming pace infecting about 5.59 million, and claiming the lives of more than 0.35 million individuals across the globe. The lack of a clinically approved vaccine or drug remains the biggest bottleneck in combating the pandemic. Drug repurposing can expedite the process of drug development by identifying known drugs which are effective against SARS-CoV-2. The SARS-CoV-2 main protease is a promising drug target due to its indispensable role in viral multiplication inside the host. In the present study an E-pharmacophore hypothesis was generated using a crystal structure of the viral protease in complex with an imidazole carbaximide inhibitor. Drugs available in the superDRUG2 database were used to identify candidate drugs for repurposing. The hits obtained from the pharmacophore based screening were further screened using a structure based approach involving molecular docking at different precisions. The binding energies of the most promising compounds were estimated using MM-GBSA. The stability of the interactions between the selected drugs and the target were further explored using molecular dynamics simulation at 100 ns. The results showed that the drugs Binifibrate and Bamifylline bind strongly to the enzyme active site and hence they can be repurposed against SARS-CoV-2. However, U.S Food and Drug Administration have withdrawn Binifibrate from the market as it was having some adverse health effects on patients.Communicated by Ramaswamy H. Sarma.

Strategy, Progress, and Challenges of Drug Repurposing for Efficient Antiviral Discovery

Emerging or re-emerging viruses are still major threats to public health. Prophylactic vaccines represent the most effective way to prevent virus infection; however, antivirals are more promising for those viruses against which vaccines are not effective enough or contemporarily unavailable. Because of the slow pace of novel antiviral discovery, the high disuse rates, and the substantial cost, repurposing of the well-characterized therapeutics, either approved or under investigation, is becoming an attractive strategy to identify the new directions to treat virus infections. In this review, we described recent progress in identifying broad-spectrum antivirals through drug repurposing. We defined the two major categories of the repurposed antivirals, direct-acting repurposed antivirals (DARA) and host-targeting repurposed antivirals (HTRA). Under each category, we summarized repurposed antivirals with potential broad-spectrum activity against a variety of viruses and discussed the possible mechanisms of action. Finally, we proposed the potential investigative directions of drug repurposing.

Lipid-lowering therapy in high cardiovascular risk patients during COVID-19 pandemic: keep focused on the target

To the Editor COVID-19 (COrona VIrus Disease) patients with cardiovascular (CV) disease, multiple CV risk factors or comorbidities (i.e., arterial hypertension and diabetes) were shown to be more prone to a worse prognosis. SARS-CoV-2 is a still unknown enemy and the role of concomitant cardiovascular therapies has been controversial in the early stages, particularly with regard to Angiotensin-Converting Enzyme inhibitors...

COVID-19 enters the expanding network of apolipoprotein E4-related pathologies

COVID-19 incidence and case fatality rates (CFR) differ among ethnicities, stimulating efforts to pinpoint genetic factors that could explain these phenomena. In this regard, the multiallelic apolipoprotein E (APOE) gene has recently been interrogated in the UK biobank cohort, demonstrating associations of the APOE ε4/ε4 genotype with COVID-19 severity and mortality. The frequency of the ε4 allele and thus the distribution of APOE ε4/ε4 genotype may differ among populations. We have assessed APOE genotypes in 1638 Greek individuals, based on haplotypes derived from SNP rs7412 and rs429358 and found reduced frequency of ε4/ε4 compared to the British cohort. Herein we discuss this finding in relation to CFR and hypothesize on the potential mechanisms linking APOE ε4/ε4 to severe COVID-19. We postulate that the metabolic deregulation ensued by APOE4, manifested by elevated cholesterol and oxidized lipoprotein levels, may be central to heightened pneumocyte susceptibility to infection and to exaggerated lung inflammation associated with the ε4/ε4 genotype. We also discuss putative dietary and pharmacological approaches for the prevention and management of COVID-19 in APOE ε4/ε4 individuals.

Lipid homeostasis and mevalonate pathway in COVID-19: Basic concepts and potential therapeutic targets

Despite encouraging progresses achieved in the management of viral diseases, efficient strategies to counteract infections are still required. The current global challenge highlighted the need to develop a rapid and cost-effective strategy to counteract the SARS-CoV-2 pandemic. Lipid metabolism plays a crucial role in viral infections. Viruses can use the host lipid machinery to support their life cycle and to impair the host immune response. The altered expression of mevalonate pathway-related genes, induced by several viruses, assures survival and spread in host tissue. In some infections, statins, HMG-CoA-reductase inhibitors, reduce cholesterol in the plasma membrane of permissive cells resulting in lower viral titers and failure to internalize the virus. Statins can also counteract viral infections through their immunomodulatory, anti-inflammatory and anti-thrombotic effects. Beyond statins, interfering with the mevalonate pathway could have an adjuvant effect in therapies aimed at mitigating endothelial dysfunction and deregulated inflammation in viral infection. In this review we depicted the historical and current evidence highlighting how lipid homeostasis and mevalonate pathway targeting represents a valid approach to rapidly neutralize viruses, focusing our attention to their potential use as effective targets to hinder SARS-CoV-2 morbidity and mortality. Pros and cons of statins and Mevalonate-pathway inhibitors have been also dissected.

Association between antecedent statin use and severe disease outcomes in COVID-19: A retrospective study with propensity score matching

Background

Statins have been associated with a reduction in inflammatory markers and improved endothelial function. Whether statins offer any benefit in COVID-19 needs to be elucidated.

Objective

To determine the association between antecedent statin use and severe disease outcomes among COVID-19 patients.

Methods

A retrospective cohort study on 1014 patients with confirmed COVID-19 diagnosis. Outcomes were mortality, need for mechanical ventilation, and intensive care admission. Patients were classified into statin-users vs statin non-users based on antecedent use of statins. Multivariable regression analysis was performed adjusting for confounders such as age, sex, race, BMI, smoking, insurance, and comorbidities. Propensity score matching was performed to achieve a 1:1 balanced cohort.

Results

A total of 1014 patients (Median age 65 (IQR 53–73); 530 (52.3%) males; 753 (74.3%) African Americans; median BMI 29.4 (IQR 25.1–35.9); 615 (60.7%) with Medicare insurance) were included in the study. About 454 patients (44.77%) were using statins as home medication. Antecedent statin use was associated with significant decrease in mortality in the total cohort (OR, 0.66; 95% CI, 0.46 – 0.95; p = 0.03). Among the propensity score matched (PSM) cohort of 466 patients (233 statin users and 233 statin non-users), all the baseline characteristics had similar distribution among the two groups. Statin users had significant reduction in mortality in the PSM cohort as well (OR, 0.56; 95% CI, 0.37 – 0.83; p = 0.004).

Conclusions

Statin use was associated with significant reduction in mortality among COVID-19 patients. These findings support the pursuit of randomized clinical trials to explore the possible benefits of statins in COVID-19.

Ebola virus glycoprotein interacts with cholesterol to enhance membrane fusion and cell entry

Cholesterol serves critical roles in enveloped virus fusion by modulating membrane properties. The glycoprotein (GP) of Ebola virus (EBOV) promotes fusion in the endosome, a process that requires the endosomal cholesterol transporter NPC1. However, the role of cholesterol in EBOV fusion is unclear. Here we show that cholesterol in GP-containing membranes enhances fusion and the membrane-proximal external region and transmembrane (MPER/TM) domain of GP interacts with cholesterol via several glycine residues in the GP2 TM domain, notably G660. Compared to wild-type (WT) counterparts, a G660L mutation caused a more open angle between MPER and TM domains in an MPER/TM construct, higher probability of stalling at hemifusion for GP2 proteoliposomes and lower cell entry of virus-like particles (VLPs). VLPs with depleted cholesterol show reduced cell entry, and VLPs produced under cholesterol-lowering statin conditions show less frequent entry than respective controls. We propose that cholesterol-TM interactions affect structural features of GP2, thereby facilitating fusion and cell entry.

Are statins beneficial for the treatment of SARS-CoV-2 infection?

Novel coronavirus disease 2019 (COVID-19) is a highly infectious, rapidly spreading viral disease and has emerged as a public health emergency of international concern. As of this time, there are no specific antiviral therapies available for the treatment of COVID-19. However, it is possible that some existing drugs, usually used for other conditions, may have some benefits. Statins have been widely reported to exert antiviral activity against many enveloped viruses by inhibiting the cholesterol biosynthesis pathway. Cholesterol likewise contributes to the coronavirus's life cycle, including viral entry, fusion and budding. In addition, statins have been ascribed beneficial anti-inflammatory, immunomodulatory effects and promote haemodynamic stability. Therefore, statins, which are cholesterol-lowering drugs with anti-inflammatory, immunomodulatory and antiviral properties, may play a role in SARS-CoV-2 therapy. The aim of the present minireview was to delineate the potential beneficial therapeutic effects of statins in treating SARS-CoV-2 infections. Nevertheless, large, randomised trials are needed to confirm the beneficial effects and safety profile of the statins in patients with SARS-CoV-2.

Statins as an adjunctive therapy for COVID-19: the biological and clinical plausibility

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has infected millions of individuals and has claimed hundreds of thousands of human lives worldwide. Patients with underlying cardiovascular conditions are at high risk for SARS-CoV-2 infection, and COVID-19 patients have high incidence of cardiovascular complications such as acute cardiac injury, arrhythmias, heart failure, and thromboembolism. The disease has no approved proven effective therapy and hence repurposing of existing approved drugs has been considered as the fastest treatment approach. Statins have been shown to exhibit lipid lowering dependent and independent cardiovascular protective effects as well as favorable effects in various other pathophysiological states. These beneficial properties of statins are a result of their multiple pleotropic effects that include, anti-inflammatory, immunomodulatory, antithrombotic and antimicrobial properties. In this review, we provide a comprehensive description of the mechanisms of the pleotropic effects of statins, the relevant pre-clinical and clinical data pertinent to their role in infections and acute lung injury, the possible cardiovascular benefits of statins in COVID-19, and the implications of the therapeutic potential of statins in COVID-19 disease. We conclude with the rationale for conducting randomized controlled trials of statins in COVID-19 disease.

Statins and PCSK9 inhibitors: What is their role in coronavirus disease 2019?

Statins and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors interfere with several pathophysiological pathways of coronavirus disease 2019 (COVID-19). Statins may have a direct antiviral effect on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by inhibiting its main protease. Statin-induced up-regulation of angiotensin-converting enzyme 2 (ACE2) may also be beneficial, whereas cholesterol reduction might significantly suppress SARS-CoV-2 by either blocking its host-cell entry through the disruption of lipid rafts or by inhibiting its replication. Available human studies have shown beneficial effects of statins and PCSK9 inhibitors on pneumonia and sepsis. These drugs may act as immunomodulators in COVID-19 and protect against major complications, such as acute respiratory distress syndrome and cytokine release syndrome. Considering their antioxidative, anti-arrhythmic, antithrombotic properties and their beneficial effect on endothelial dysfunction, along with the increased risk of mortality of patients at high cardiovascular risk infected by SARS-CoV-2, statins and PCSK9 inhibitors might prove effective against the cardiovascular and thromboembolic complications of COVID-19. On the whole, randomized clinical trials are needed to establish routine use of statins and PCSK9 inhibitors in the treatment of SARS-CoV-2 infection. In the meantime, it is recommended that lipid-lowering therapy should not be discontinued in COVID-19 patients unless otherwise indicated.

The axonal sorting activity of pseudorabies virus Us9 protein depends on the state of neuronal maturation

Alpha-herpesviruses establish a life-long infection in the nervous system of the affected host; while this infection is restricted to peripheral neurons in a healthy host, the reactivated virus can spread within the neuronal circuitry, such as to the brain, in compromised individuals and lead to adverse health outcomes. Pseudorabies virus (PRV), an alpha-herpesvirus, requires the viral protein Us9 to sort virus particles into axons and facilitate neuronal spread. Us9 sorts virus particles by mediating the interaction of virus particles with neuronal transport machinery. Here, we report that Us9-mediated regulation of axonal sorting also depends on the state of neuronal maturation. Specifically, the development of dendrites and axons is accompanied with proteomic changes that influence neuronal processes. Immature superior cervical ganglionic neurons (SCGs) have rudimentary neurites that lack markers of mature axons. Immature SCGs can be infected by PRV, but they show markedly reduced Us9-dependent regulation of sorting, and increased Us9-independent transport of particles into neurites. Mature SCGs have relatively higher abundances of proteins characteristic of vesicle-transport machinery. We also identify Us9-associated neuronal proteins that can contribute to axonal sorting and subsequent anterograde spread of virus particles in axons. We show that SMPD4/nsMase3, a sphingomyelinase abundant in lipid-rafts, associates with Us9 and is a negative regulator of PRV sorting into axons and neuronal spread, a potential antiviral function.

A connectivity map-based drug repurposing study and integrative analysis of transcriptomic profiling of SARS-CoV-2 infection

AIMS

The recent outbreak of COVID-19 has become a global health concern. There are currently no effective treatment strategies and vaccines for the treatment or prevention of this fatal disease. The current study aims to determine promising treatment options for the COVID-19 through a computational drug repurposing approach.

MATERIALS AND METHODS

In this study, we focus on differentially expressed genes (DEGs), detected in SARS-CoV-2 infected cell lines including "the primary human lung epithelial cell line NHBE" and "the transformed lung alveolar cell line A549". Next, the identified DEGs are used in the connectivity map (CMap) analysis to identify similarly acting therapeutic candidates. Furthermore, to interpret lists of DEGs, pathway enrichment and protein network analysis are performed. Genes are categorized into easily interpretable pathways based on their biological functions, and overrepresentation of each pathway is tested in comparison to what is expected randomly.

KEY FINDINGS

The results suggest the effectiveness of lansoprazole, folic acid, sulfamonomethoxine, tolnaftate, diclofenamide, halcinonide, saquinavir, metronidazole, ebselen, lidocaine and benzocaine, histone deacetylase (HDAC) inhibitors, heat shock protein 90 (HSP90) inhibitors, and many other clinically approved drugs as potent drugs against COVID-19 outbreak.

SIGNIFICANCE

Making new drugs remain a lengthy process, so the drug repurposing approach provides an insight into the therapeutics that might be helpful in this pandemic. In this study, pathway enrichment and protein network analysis are also performed, and the effectiveness of some drugs obtained from the CMap analysis has been investigated according to previous researches.

Hantavirus Infection Is Inhibited by Griffithsin in Cell Culture

Andes virus (ANDV) and Sin Nombre virus (SNV), highly pathogenic hantaviruses, cause hantavirus pulmonary syndrome in the Americas. Currently no therapeutics are approved for use against these infections. Griffithsin (GRFT) is a high-mannose oligosaccharide-binding lectin currently being evaluated in phase I clinical trials as a topical microbicide for the prevention of human immunodeficiency virus (HIV-1) infection (ClinicalTrials.gov Identifiers: NCT04032717, NCT02875119) and has shown broad-spectrum in vivo activity against other viruses, including severe acute respiratory syndrome coronavirus, hepatitis C virus, Japanese encephalitis virus, and Nipah virus. In this study, we evaluated the in vitro antiviral activity of GRFT and its synthetic trimeric tandemer 3mGRFT against ANDV and SNV. Our results demonstrate that GRFT is a potent inhibitor of ANDV infection. GRFT inhibited entry of pseudo-particles typed with ANDV envelope glycoprotein into host cells, suggesting that it inhibits viral envelope protein function during entry. 3mGRFT is more potent than GRFT against ANDV and SNV infection. Our results warrant the testing of GRFT and 3mGRFT against ANDV infection in animal models.

CXCL10 Signaling Contributes to the Pathogenesis of Arthritogenic Alphaviruses

Emerging and re-emerging arthritogenic alphaviruses, such as Chikungunya virus (CHIKV) and O'nyong nyong virus, cause acute and chronic crippling arthralgia associated with inflammatory immune responses. Approximately 50% of CHIKV-infected patients suffer from rheumatic manifestations that last 6 months to years. However, the physiological functions of individual immune signaling pathways in the pathogenesis of alphaviral arthritis remain poorly understood. Here, we report that a deficiency in CXCL10, which is a chemoattractant for monocytes/macrophages/T cells, led to the same viremia as wild-type animals, but fewer immune infiltrates and lower viral loads in footpads at the peak of arthritic disease (6-8 days post infection). Macrophages constituted the largest immune cell population in footpads following infection, and were significantly reduced in Cxcl10^-/- mice. The viral RNA loads in neutrophils and macrophages were reduced in Cxcl10^-/- compared to wild-type mice. In summary, our results demonstrate that CXCL10 signaling promotes the pathogenesis of alphaviral disease and suggest that CXCL10 may be a therapeutic target for mitigating alphaviral arthritis.

Statins: Could an old friend help in the fight against COVID-19?

The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has overwhelmed healthcare systems requiring the rapid development of treatments, at least, to reduce COVID-19 severity. Drug repurposing offers a fast track. Here, we discuss the potential beneficial effects of statins in COVID-19 patients based on evidence that they may target virus receptors, replication, degradation, and downstream responses in infected cells, addressing both basic research and epidemiological information. Briefly, statins could modulate virus entry, acting on the SARS-CoV-2 receptors, ACE2 and CD147, and/or lipid rafts engagement. Statins, by inducing autophagy activation, could regulate virus replication or degradation, exerting protective effects. The well-known anti-inflammatory properties of statins, by blocking several molecular mechanisms, including NF-κB and NLRP3 inflammasomes, could limit the "cytokine storm" in severe COVID-19 patients which is linked to fatal outcome. Finally, statin moderation of coagulation response activation may also contribute to improving COVID-19 outcomes. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.

Antiviral effects of statins

Introducing statins as possible widely-available drugs for the treatment of viral infections requires an in depth review of their antiviral properties. Despite some inconsistency, a large body of literature data from experimental and clinical studies suggest that statins may have a role in the treatment of viral infections due to their immunomodulatory properties as well as their ability to inhibit viral replication. In the present review, the role that statins may play while interacting with the immune system during viral infections and the possible inhibitory effects of statins on different stages of virus cell cycle (i.e., from fusion with host cell membranes to extracellular release) and subsequent virus transmission are described. Specifically, cholesterol-dependent and cholesterol-independent mechanisms of the antiviral effects of statins are reported.

Potential Anti-COVID-19 Therapeutics that Block the Early Stage of the Viral Life Cycle: Structures, Mechanisms, and Clinical Trials

The ongoing pandemic of coronavirus disease-2019 (COVID-19) is being caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The disease continues to present significant challenges to the health care systems around the world. This is primarily because of the lack of vaccines to protect against the infection and the lack of highly effective therapeutics to prevent and/or treat the illness. Nevertheless, researchers have swiftly responded to the pandemic by advancing old and new potential therapeutics into clinical trials. In this review, we summarize potential anti-COVID-19 therapeutics that block the early stage of the viral life cycle. The review presents the structures, mechanisms, and reported results of clinical trials of potential therapeutics that have been listed in clinicaltrials.gov. Given the fact that some of these therapeutics are multi-acting molecules, other relevant mechanisms will also be described. The reviewed therapeutics include small molecules and macromolecules of sulfated polysaccharides, polypeptides, and monoclonal antibodies. The potential therapeutics target viral and/or host proteins or processes that facilitate the early stage of the viral infection. Frequent targets are the viral spike protein, the host angiotensin converting enzyme 2, the host transmembrane protease serine 2, and clathrin-mediated endocytosis process. Overall, the review aims at presenting update-to-date details, so as to enhance awareness of potential therapeutics, and thus, to catalyze their appropriate use in combating the pandemic.

Statins and the COVID-19 main protease: in silico evidence on direct interaction

INTRODUCTION

No proven drug and no immunisation are yet available for COVID-19 disease. The SARS-CoV-2 main protease (Mpro), a key coronavirus enzyme, which is a potential drug target, has been successfully crystallised. There is evidence suggesting that statins exert anti-viral activity and may block the infectivity of enveloped viruses. The aim of this study was to assess whether statins are potential COVID-19 Mpro inhibitors, using a molecular docking study.

MATERIAL AND METHODS

Molecular docking was performed using AutoDock/Vina, a computational docking program. SARS-CoV-2 Mpro was docked with all statins, while antiviral and antiretroviral drugs - favipiravir, nelfinavir, and lopinavir - were used as standards for comparison.

RESULTS

The binding energies obtained from the docking of 6LU7 with native ligand favipiravir, nelfinavir, lopinavir, simvastatin, rosuvastatin, pravastatin, pitavastatin, lovastatin, fluvastatin, and atorvastatin were -6.8, -5.8, -7.9, -7.9, -7.0, -7.7, -6.6, -8.2, -7.4, -7.7, and -6.8 kcal/mol, respectively. The number of hydrogen bonds between statins and amino acid residues of Mpro were 7, 4, and 3 for rosuvastatin, pravastatin, and atorvastatin, respectively, while other statins had two hydrogen bonds.

CONCLUSIONS

These results indicate, based upon the binding energy of pitavastatin, rosuvastatin, lovastatin, and fluvastatin, that statins could be efficient SARS-CoV-2 Mpro inhibitors. This is supported by the fact that the effects of some statins, especially pitavastatin, have a binding energy that is even greater than that of protease or polymerase inhibitors. However, further research is necessary to investigate their potential use as drugs for COVID-19.

[18F]Atorvastatin: synthesis of a potential molecular imaging tool for the assessment of statin-related mechanisms of action

Background

Statins are lipid-lowering agents that inhibit cholesterol synthesis and are clinically used in the primary and secondary prevention of cardiovascular diseases. However, a considerable group of patients does not respond to statin treatment, and the reason for this is still not completely understood. [¹⁸F]Atorvastatin, the ¹⁸F-labeled version of one of the most widely prescribed statins, may be a useful tool for statin-related research.

Results

[¹⁸F]Atorvastatin was synthesized via an optimized ruthenium-mediated late-stage ¹⁸F-deoxyfluorination. The defluoro-hydroxy precursor was produced via Paal-Knorr pyrrole synthesis and was followed by coordination of the phenol to a ruthenium complex, affording the labeling precursor in approximately 10% overall yield. Optimization and automation of the labeling procedure reliably yielded an injectable solution of [¹⁸F]atorvastatin in 19% ± 6% (d.c.) with a molar activity of 65 ± 32 GBq·μmol⁻¹. Incubation of [¹⁸F]atorvastatin in human serum did not lead to decomposition. Furthermore, we have shown the ability of [¹⁸F]atorvastatin to cross the hepatic cell membrane to the cytosolic and microsomal fractions where HMG-CoA reductase is known to be highly expressed. Blocking assays using rat liver sections confirmed the specific binding to HMG-CoA reductase. Autoradiography on rat aorta stimulated to develop atherosclerotic plaques revealed that [¹⁸F]atorvastatin significantly accumulates in this tissue when compared to the healthy model.

Conclusions

The improved ruthenium-mediated ¹⁸F-deoxyfluorination procedure overcomes previous hurdles such as the addition of salt additives, the drying steps, or the use of different solvent mixtures at different phases of the process, which increases its practical use, and may allow faster translation to clinical settings. Based on tissue uptake evaluations, [¹⁸F]atorvastatin showed the potential to be used as a tool for the understanding of the mechanism of action of statins. Further knowledge of the in vivo biodistribution of [¹⁸F]atorvastatin may help to better understand the origin of off-target effects and potentially allow to distinguish between statin-resistant and non-resistant patients.

Rosuvastatin Enhances VSV-G Lentiviral Transduction of NK Cells via Upregulation of the Low-Density Lipoprotein Receptor

Adoptive natural killer (NK) cell therapy is attaining promising clinical outcomes in recent years, but improvements are needed. Genetic modification of NK cells with a tumor antigen-specific receptor on their surface coupled to intracellular signaling domains may lead to enhanced cytotoxicity against malignant cells. One of the most common approaches is by lentivirus-mediated transduction. However, NK cells are difficult to transduce and various methods have been attempted with different success rates. Because the low-density lipoprotein-receptor (LDLR) is the receptor of vesicular stomatitis virus (VSV) and is expressed only at low levels on NK cells, we tested the potential of 5 statins and 5 non-statin compounds to increase the LDLR expression, thereby facilitating viral transduction. We found that the transduction efficiency of VSV-G pseudotyped lentivirus is augmented by statins that induced higher LDLR expression. In both NK-92 cells and primary NK cells, the transduction efficiency increased after treatment with statins. Furthermore, statins have been reported to suppress NK cell cytotoxicity; however, we showed that this can be completely reversed by adding geranylgeranyl-pyrophosphate (GGPP). Among the statins tested, we found that the combination of rosuvastatin with GGPP most potently improved viral transduction without affecting the cytotoxic properties of the NK cells.

Lipophilic statins inhibit Zika virus production in Vero cells

Zika virus (ZIKV) is a mosquito-borne member of the Flaviviridae family. ZIKV infection has been associated with neurological complications such as microcephaly in newborns and Guillain-Barré syndrome in adults; thus, therapeutic agents are urgently needed. Statins are clinically approved for lowering cholesterol levels to prevent cardiovascular disease but have shown potential as antiviral drugs. In this study, we explored the possibility of utilizing statins as anti-ZIKV drugs. We found that, generally, lipophilic statins (atorvastatin, cerivastatin, fluvastatin, lovastatin, mevastatin, and simvastatin) could reduce ZIKV production in vitro and result in smaller foci of infection. Time-of-drug-addition assay revealed that early treatment with statins is more beneficial than late treatment; however, statins could not completely inhibit the entry stage of ZIKV infection. Furthermore, individual lipophilic statins differed in anti-ZIKV capacity, with fluvastatin being the most efficient at low concentrations. Taken together, this study shows that statins or their derivatives have the potential to be used as anti-ZIKV therapeutic agents.

Inhibitors of signal peptide peptidase and subtilisin/kexin-isozyme 1 inhibit Ebola virus glycoprotein-driven cell entry by interfering with activity and cellular localization of endosomal cathepsins

Emerging viruses such as severe fever and thrombocytopenia syndrome virus (SFTSV) and Ebola virus (EBOV) are responsible for significant morbidity and mortality. Host cell proteases that process the glycoproteins of these viruses are potential targets for antiviral intervention. The aspartyl protease signal peptide peptidase (SPP) has recently been shown to be required for processing of the glycoprotein precursor, Gn/Gc, of Bunyamwera virus and for viral infectivity. Here, we investigated whether SPP is also required for infectivity of particles bearing SFTSV-Gn/Gc. Entry driven by the EBOV glycoprotein (GP) and the Lassa virus glycoprotein (LASV-GPC) depends on the cysteine proteases cathepsin B and L (CatB/CatL) and the serine protease subtilisin/kexin-isozyme 1 (SKI-1), respectively, and was examined in parallel for control purposes. We found that inhibition of SPP and SKI-1 did not interfere with SFTSV Gn + Gc-driven entry but, unexpectedly, blocked entry mediated by EBOV-GP. The inhibition occurred at the stage of proteolytic activation and the SPP inhibitor was found to block CatL/CatB activity. In contrast, the SKI-1 inhibitor did not interfere with CatB/CatL activity but disrupted CatB localization in endo/lysosomes, the site of EBOV-GP processing. These results underline the potential of protease inhibitors for antiviral therapy but also show that previously characterized compounds might exert broader specificity than initially appreciated and might block viral entry via diverse mechanisms.

A genome-wide CRISPR screen identifies N-acetylglucosamine-1-phosphate transferase as a potential antiviral target for Ebola virus

There are no approved therapies for Ebola virus infection. Here, to find potential therapeutic targets, we perform a screen for genes essential for Ebola virus (EBOV) infection. We identify GNPTAB, which encodes the α and β subunits of N-acetylglucosamine-1-phosphate transferase. We show that EBOV infection of a GNPTAB knockout cell line is impaired, and that this is reversed by reconstituting GNPTAB expression. Fibroblasts from patients with mucolipidosis II, a disorder associated with mutations in GNPTAB, are refractory to EBOV, whereas cells from their healthy parents support infection. Impaired infection correlates with loss of the expression of cathepsin B, known to be essential for EBOV entry. GNPTAB activity is dependent upon proteolytic cleavage by the SKI-1/S1P protease. Inhibiting this protease with the small-molecule PF-429242 blocks EBOV entry and infection. Disruption of GNPTAB function may represent a strategy for a host-targeted therapy for EBOV.

Genetic screens are important tools to identify host factors associated with viral infections. Here, Flint et al. perform a genome-wide CRISPR screen using infectious Ebola virus (EBOV) and show that the host transferase GNPTAB is required for EBOV infection and a potential target for antiviral therapies

What treating Ebola means for pandemic influenza

Almost all new treatments being developed for the next influenza pandemic target the virus. During the Ebola crisis in West Africa, patients were treated with an inexpensive generic statin/angiotensin receptor blocker combination that appeared to greatly improve survival. These drugs target the host response, not the virus, and probably reverse endothelial dysfunction. Scientists and health officials have shown little interest in this idea. Yet, during the early months of the next pandemic, vaccines will be unavailable and treatment options will be limited. Physicians should be prepared to undertake clinical trials of widely available generic drugs to determine whether they improve survival in patients with seasonal influenza, other emerging virus diseases, and other forms of acute critical illness. Public health officials should give these studies their strong support. If successful, they will suggest a 'bottom up' approach to patient care that could be implemented worldwide on the first pandemic day.