Andrographolide Prevents EV-D68 Replication by Inhibiting the Acidification of Virus-Containing Endocytic Vesicles

Andrographolide Attenuates RSV-induced Inflammation by Suppressing Apoptosis and Promoting Pyroptosis after Respiratory Syncytial Virus Infection In Vitro

BACKGROUND

Respiratory syncytial virus (RSV), which is the predominant viral pathogen responsible for causing acute lower respiratory tract infections in children, currently lacks specific therapeutic drugs. Despite andrographolide's demonstrated effectiveness against various viral infections, its effects on RSV infection remain unclear.

METHODS

In this study, RSV infection and andrographolide-intervened A549 cell lines were used. The virus load of RSV and the levels of IL-6 and IL-8 in the cell supernatant were quantified. The potential targets of andrographolide in the treatment of RSV-infected airway epithelial cells were analyzed using the Gene Expression Omnibus (GEO) database and the PharmMapper Database, and the changes in mRNA expression of these target genes were measured. To further illustrate the effect of andrographolide on the death pattern of RSV-infected airway epithelial cells, Annexin V-FITC/PI apoptosis assays and Western blotting were conducted.

RESULTS

Andrographolide decreased the viral load and attenuated IL-6 and IL-8 levels in cell supernatant post-RSV infection. A total of 25 potential targets of andrographolide in the treatment of RSV-infected airway epithelial cells were discovered, and CASP1, CCL5, JAK2, and STAT1 were identified as significant players. Andrographolide noticeably suppressed the increased mRNA expressions of these genes post-RSV infection as well as IL-1β. The flow cytometry analysis demonstrated that andrographolide alleviated apoptosis in RSV-infected cells. Additionally, RSV infection decreased the protein levels of caspase-1, cleaved caspase-1, cleaved IL-1β, N-terminal of GSDMD, and Bcl-2. Conversely, andrographolide increased their levels.

CONCLUSION

These results suggest that andrographolide may reduce RSV-induced inflammation by suppressing apoptosis and promoting pyroptosis in epithelial cells, leading to effective viral clearance.

Repurposing of Plant-based Antiviral Molecules for the Treatment of COVID-19

COVID-19, stemming from SARS-CoV-2, poses a formidable threat to global healthcare, with a staggering 77 million confirmed cases and 690,067 deaths recorded till December 24, 2023. Given the absence of specific drugs for this viral infection, the exploration of novel antiviral compounds becomes imperative. High-throughput technologies are actively engaged in drug discovery, and there is a parallel effort to repurpose plant-based molecules with established antiviral properties. In this context, the review meticulously delves into the potential of plant-based folk remedies and existing molecules. These substances have showcased substantial viral inhibition in diverse in vivo, in silico, and in vitro studies, particularly against critical viral protein targets, including SARS-CoV-2. The findings position these plant-based molecules as promising antiviral drug candidates for the swift advancement of treatments for COVID-19. It is noteworthy that the inherent attributes of these plant-based molecules, such as their natural origin, potency, safety, and cost-effectiveness, contribute to their appeal as lead candidates. The review advocates for further exploration through comprehensive in vivo studies conducted on animal models, emphasizing the potential of plant-based compounds to help in the ongoing quest to develop effective antivirals against COVID-19.

An unexpected, pH-sensitive step of the enterovirus D68 lifecycle

Enterovirus D68 (EV-D68) contributes significantly to pathogen-induced respiratory illnesses and severe neurological disorders like acute flaccid myelitis. We lack EV-D68 preventive measures, and knowledge of its molecular and cellular biology is incomplete. Multiple studies have highlighted the role of membrane compartments and autophagy during picornavirus multiplication. Galitska et al. found that EV-D68 also exploits cellular autophagic compartments and relies on autophagic machinery as pro-viral factors (G. Galitska, A. Jassey, M. A. Wagner, N. Pollack, et al., mBio e02141-23, 2023, https://doi.org/10.1128/mbio.02141-23). Surprisingly, failure of the autophagic compartment to acidify early during EV-D68 infection causes a delay in RNA synthesis that has not been reported for other enteroviruses. This delay appears to reflect the inability of viral proteins 2B and 3A to engage membranes stably, leading to their degradation in the cytoplasm. Observations like this underscore the importance of studying individual members of the virus genus. It will be interesting to understand how this phenomenon connects to EV-D68 pathogenesis, if at all.

Enterovirus D68 capsid formation and stability requires acidic compartments

IMPORTANCE

The respiratory picornavirus enterovirus D68 is a causative agent of acute flaccid myelitis, a childhood paralysis disease identified in the last decade. Poliovirus, another picornavirus associated with paralytic disease, is a fecal-oral virus that survives acidic environments when passing from host to host. Here, we follow up on our previous work showing a requirement for acidic intracellular compartments for maturation cleavage of poliovirus particles. Enterovirus D68 requires acidic vesicles for an earlier step, assembly, and maintenance of viral particles themselves. These data have strong implications for the use of acidification blocking treatments to combat enterovirus diseases.

Enterovirus D68 capsid formation and stability requires acidic compartments

Enterovirus D68 (EV-D68), a picornavirus traditionally associated with respiratory infections, has recently been linked to a polio-like paralytic condition known as acute flaccid myelitis (AFM). EV-D68 is understudied, and much of the field's understanding of this virus is based on studies of poliovirus. For poliovirus, we previously showed that low pH promotes virus capsid maturation, but here we show that, for EV-D68, inhibition of compartment acidification during a specific window of infection causes a defect in capsid formation and maintenance. These phenotypes are accompanied by radical changes in the infected cell, with viral replication organelles clustering in a tight juxtanuclear grouping. Organelle acidification is critical during a narrow window from 3-4hpi, which we have termed the "transition point," separating translation and peak RNA replication from capsid formation, maturation and egress. Our findings highlight that acidification is crucial only when vesicles convert from RNA factories to virion crucibles.

Andrographolide exerts anti-respiratory syncytial virus activity by up-regulating heme oxygenase-1 independent of interferon responses in human airway epithelial cells

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of mortality and morbidity in children under the age of five. Despite this, there is still a lack of safe and effective vaccines and antiviral agents for clinical use. Andrographolide exerts antiviral functions against a variety of viruses, but whether (and how) it exerts antiviral effects on RSV remains unclear.

METHODS AND RESULTS

In vitro RSV infection models using A549 and 16HBE cell lines were established, and the effects of andrographolide on RSV were analyzed via RSV N gene load and proinflammatory cytokine levels. The RNA transcriptome was sequenced, and data were analyzed by R software. Andrographolide-related target genes were extracted via network pharmacology using online databases. Lentiviral transfection was applied to knockdown the heme oxygenase-1 gene (Hmox1, HO-1). Results showed that andrographolide suppressed RSV replication and attenuated subsequent inflammation. Network pharmacology and RNA sequencing analysis indicated that the hub gene HO-1 may play a pivotal role in the anti-RSV effects of andrographolide. Furthermore, andrographolide exerted antiviral effects against RSV partially by inducing HO-1 but did not activate the antiviral interferon response.

CONCLUSION

Our findings demonstrated that andrographolide exerted anti-RSV activity by up-regulating HO-1 expression in human airway epithelial cells, providing novel insights into potential therapeutic targets and drug repurposing in RSV infection.

Andrographolide and Deoxyandrographolide Inhibit Protease and IFN-Antagonist Activities of Foot-and-Mouth Disease Virus 3Cpro

Simple Summary

Foot-and-Mouth disease (FMD) is a re-emerging infectious disease that poses a negative impact on livestock production and economics worldwide. It is also endemic in underdeveloped and developing countries, mostly in tropical areas. The control of this highly contagious disease requires a combination of different strategies, including the culling of infected animals, reducing animal movement, and vaccination. Although vaccination is effective, there remains a non-protective interval after immunization. Antiviral agents that can inhibit FMD virus (FMDV) could reduce the shedding of viruses in terms of quantity and duration, which could assist other control measures to contain FMD spreading. Antiviral activities of plant-based products, including andrographolides, have been demonstrated in several studies. Andrographolides are a group of phytochemical compounds derived from medicinal plants in the genus Andrographis, which are abundant in Asia, a hot spot of FMDV outbreaks. We found that andrographolides could inhibit FMDV replication by targeting a viral protease, namely 3C^pro. FMDV 3C^pro is the main protease essential for the virus life cycle. The 3C^pro also counteracts type I interferon, which is the frontline antiviral cytokine. We also revealed the intracellular mechanisms by which the andrographolides inhibited both protease and IFN antagonist activities of the 3C^pro.

Abstract

Foot-and mouth-disease (FMD) caused by the FMD virus (FMDV) is highly contagious and negatively affects livestock worldwide. The control of the disease requires a combination of measures, including vaccination; however, there is no specific treatment available. Several studies have shown that plant-derived products with antiviral properties were effective on viral diseases. Herein, antiviral activities of andrographolide (AGL), deoxyandrographolide (DAG), and neoandrographolide (NEO) against FMDV serotype A were investigated using an in vitro cell-based assay. The results showed that AGL and DAG inhibited FMDV in BHK-21 cells. The inhibitory effects of AGL and DAG were evaluated by RT-qPCR and exhibited EC50 values of 52.18 ± 0.01 µM (SI = 2.23) and 36.47 ± 0.07 µM (SI = 9.22), respectively. The intracellular protease assay revealed that AGL and DAG inhibited FMDV 3C^pro with IC50 of 67.43 ± 0.81 and 25.58 ± 1.41 µM, respectively. Additionally, AGL and DAG significantly interfered with interferon (IFN) antagonist activity of the 3C^pro by derepressing interferon-stimulating gene (ISGs) expression. The molecular docking confirmed that the andrographolides preferentially interacted with the 3C^pro active site. However, NEO had no antiviral effect in any of the assays. Conclusively, AGL and DAG inhibited FMDV serotype A by interacting with the 3C^pro and hindered its protease and IFN antagonist activities.

Discovery of Novel Andrographolide Derivatives as Antiviral Inhibitors against Human Enterovirus A71

Hand-foot-and-mouth disease (HFMD) caused by human enterovirus A71 (EV-A71) infection has been associated with severe neurological complications. With the lack of an internationally approved antiviral, coupled with a surge in outbreaks globally, EV-A71 has emerged as a neurotropic virus of high clinical importance. Andrographolide has many pharmacological effects including antiviral activity and its derivative, andrographolide sulfonate, has been used in China clinically to treat EV-A71 infections. This study sought to identify novel andrographolide derivatives as EV-A71 inhibitors and elucidate their antiviral mode of action. Using an immunofluorescence-based phenotypic screen, we identified novel EV-A71 inhibitors from a 344-compound library of andrographolide derivatives and validated them with viral plaque assays. Among these hits, ZAF-47, a quinolinoxy-andrographolide, was selected for downstream mechanistic studies. It was found that ZAF-47 acts on EV-A71 post-entry stages and inhibits EV-A71 protein expression. Subsequent luciferase studies confirm that ZAF-47 targets EV-A71 genome RNA replication specifically. Unsuccessful attempts in generating resistant mutants led us to believe a host factor is likely to be involved which coincide with the finding that ZAF-47 exhibits broad-spectrum antiviral activity against other enteroviruses (CV-A16, CV-A6, Echo7, CV-B5, CV-A24 and EV-D68). Furthermore, ZAF-46 and ZAF-47, hits from the screen, were derivatives of the same series containing quinolinoxy and olefin modifications, suggesting that an andrographolide scaffold mounted with these unique moieties could be a potential anti-EV-A71/HFMD strategy.

Natural immunity boosters as therapeutic interventions in the era of COVID-19 pandemic

COVID-19, a pandemic caused by SARS-CoV2 has been spread all over the world and is responsible for serious fatalities. SARS-CoV2 is included in the family of β-coronavirus that affects pulmonary gas exchange and triggers cytokines storm. Vigorous inflammation, hyper-coagulation, a decrease in lymphocytic count and an increase in neutrophilic count are observed in the second week after the onset of disease. Fever, dry cough, sneezing, shortness of breath and respiratory distress are the symptoms of COVID-19. Different preventive measures are taken to prevent the attack of coronavirus amongst social distancing, vaccination, wearing gloves and face masks and the use of sanitizers plays pivotal role. People with weak immunity are more susceptible to the attack of coronavirus. Various natural immunity boosters are known for their immune boosting properties among them are vitamin C, D, and B complex, medicinal mushrooms, plant-based stuff and minerals play important role by increasing the beneficial flora of human body. All these natural immunity boosters improve the innate and adaptive immune response against coronavirus. Hence, we conclude that the use of natural immunity boosters prevents the attack of coronavirus and make a person stronger against the suspected attack of COVID-19 and/or other viral diseases.

Insight into the pharmacological effects of andrographolide in musculoskeletal disorders

Andrographis paniculata (A. paniculata) is a traditional herbal medicine that has been widely used in Asian countries for hundreds of years. Andrographolide (AG) is a diterpene lactone extracted from A. paniculata. Owing to the in-depth study of pharmacological mechanisms, the therapeutic potential of AG, including its anti-inflammatory, anti-tumor, and immunoregulatory attributes, has attracted the attention of many researchers. Studies testing the therapeutic effects of AG have demonstrated desirable results in the treatment of a variety of clinical diseases. With high safety and various biological functions, AG might be a promising candidate for the treatment of musculoskeletal disorders. Here, we review all available literatures to summarize the pharmacological effects of AG and facilitate further researches on musculoskeletal diseases.

A Review of Medicinal Plants with Antiviral Activity Available in Bangladesh and Mechanistic Insight Into Their Bioactive Metabolites on SARS-CoV-2, HIV and HBV

Currently, viral infection is the most serious health issue which causing unexpected higher rate of death globally. Many viruses are not yet curable, such as corona virus-2 (SARS-CoV-2), human immunodeficiency virus (HIV), hepatitis virus, human papilloma virus and so others. Furthermore, the toxicities and ineffective responses to resistant strains of synthetic antiviral drugs have reinforced the search of effective and alternative treatment options, such as plant-derived antiviral drug molecules. Therefore, in the present review, an attempt has been taken to summarize the medicinal plants reported for exhibiting antiviral activities available in Bangladesh along with discussing the mechanistic insights into their bioactive components against three most hazardous viruses, namely SARS-CoV-2, HIV, and HBV. The review covers 46 medicinal plants with antiviral activity from 25 families. Among the reported 79 bioactive compounds having antiviral activities isolated from these plants, about 37 of them have been reported for significant activities against varieties of viruses. Hesperidin, apigenin, luteolin, seselin, 6-gingerol, humulene epoxide, quercetin, kaempferol, curcumin, and epigallocatechin-3-gallate (EGCG) have been reported to inhibit multiple molecular targets of SARS-CoV-2 viral replication in a number of in silico investigations. Besides, numerous in silico, in vitro, and in vivo bioassays have been demonstrated that EGCG, anolignan-A, and B, ajoene, curcumin, and oleanolic acid exhibit anti-HIV activity while piperine, ursolic acid, oleanolic acid, (+)-cycloolivil-4'-O-β-d-glucopyranoside, quercetin, EGCG, kaempferol, aloin, apigenin, rosmarinic acid, andrographolide, and hesperidin possess anti-HBV activity. Thus, the antiviral medicinal plants and the isolated bioactive compounds may be considered for further advanced investigations with the aim of the development of effective and affordable antiviral drugs.

Andrographolide: A review of its pharmacology, pharmacokinetics, toxicity and clinical trials and pharmaceutical researches

Andrographis paniculata (Burm. f.) Wall. ex Nees, a renowned herb medicine in China, is broadly utilized in traditional Chinese medicine (TCM) for the treatment of cold and fever, sore throat, sore tongue, snake bite with its excellent functions of clearing heat and toxin, cooling blood and detumescence from times immemorial. Modern pharmacological research corroborates that andrographolide, the major ingredient in this traditional herb, is the fundamental material basis for its efficacy. As the main component of Andrographis paniculata (Burm. f.) Wall. ex Nees, andrographolide reveals numerous therapeutic actions, such as antiinflammatory, antioxidant, anticancer, antimicrobial, antihyperglycemic and so on. However, there are scarcely systematic summaries on the specific mechanism of disease treatment and pharmacokinetics. Moreover, it is also found that it possesses easily ignored security issues in clinical application, such as nephrotoxicity and reproductive toxicity. Thereby it should be kept a lookout over in clinical. Besides, the relationship between the efficacy and security issues of andrographolide should be investigated and evaluated scientifically. In this review, special emphasis is given to andrographolide, a multifunctional natural terpenoids, including its pharmacology, pharmacokinetics, toxicity and pharmaceutical researches. A brief overview of its clinical trials is also presented. This review intends to systematically and comprehensively summarize the current researches of andrographolide, which is of great significance for the development of andrographolide clinical products. Noteworthy, those un-cracked issues such as specific pharmacological mechanisms, security issues, as well as the bottleneck in clinical transformation, which detailed exploration and excavation are still not to be ignored before achieving integration into clinical practice. In addition, given that current extensive clinical data do not have sufficient rigor and documented details, more high-quality investigations in this field are needed to validate the efficacy and/or safety of many herbal products.

Andrographolide: A Herbal-Chemosynthetic Approach for Enhancing Immunity, Combating Viral Infections, and Its Implication on Human Health

Plants consistently synthesize and accumulate medically valuable secondary metabolites which can be isolated and clinically tested under in vitro conditions. An advancement with such important phytochemical production has been recognized and utilized as herbal drugs. Bioactive andrographolide (AGL; C20H30O5) isolated from Andrographis paniculate (AP) (Kalmegh) is a diterpenoid lactones having multifunctional medicinal properties including anti-manic, anti-inflammatory, liver, and lung protective. AGL is known for its immunostimulant activity against a variety of microbial infections thereby, regulating classical and alternative macrophage activation, Ag-specific antibody production during immune disorder therapy. In vitro studies with AGL found it to be effective against multiple tumors, neuronal disorders, diabetes, pneumonia, fibrosis, and other diverse therapeutic misadventures. Generally, virus-based diseases like ZIKA, influenza A virus subtype (H1NI), Ebola (EBOV), Dengue (DENV), and coronavirus (COVID-19) epidemics have greatly increased scientific interest and demands to develop more effective and economical immunomodulating drugs with minimal side effects. Trials and in vitro pharmacological studies with AGL and medicinally beneficial herbs might contribute to benefit the human population without using chemical-based synthetic drugs. In this review, we have discussed the possible role of AGL as a promising herbal-chemo remedy during human diseases, viral infections and as an immunity booster.

Discovery of 14S-(2'-chloro-4'-nitrophenoxy)-8R/S,17-epoxy andrographolide as EV-A71 infection inhibitor

Human enterovirus A71 (EV-A71) is a major etiological agent of hand-foot-and-mouth disease (HFMD) and there is presently no internationally approved antiviral against EV-A71. In this study, it is disclosed that 14S-(2'-chloro-4'-nitrophenoxy)-8R/S,17-epoxy andrographolide (2) was discovered to be an effective inhibitor against EV-A71 infection showing significant reduction of viral titre. In addition to EV-A71, compound 2 exerts broad-spectrum antiviral effects against other enteroviruses. It is revealed that compound 2 inhibits the post-entry stages of EV-A71 viral replication cycle and significantly reduces viral protein expression of structural proteins such as VP0 and VP2 via inhibiting EV-A71 RNA replication. Moreover, the inhibitory property of compound 2 is specific to viral RNA replication. Furthermore, compound 2 is more likely to target a host factor in EV-A71 RNA replication. As a result, introduction of epoxide at positions 8 and 17 of andrographolide is effective for anti-EV-A71 infection and is a potential anti-EV-A71 strategy. Further work to discover more potent andrographolide derivatives and elucidate comprehensive SAR is under way.

The viral capsid as novel nanomaterials for drug delivery

The purpose of this review is to highlight recent scientific developments and provide an overview of virus self-assembly and viral particle dynamics. Viruses are organized supramolecular structures with distinct yet related features and functions. Plant viruses are extensively used in biotechnology, and virus-like particulate matter is generated by genetic modification. Both provide a material-based means for selective distribution and delivery of drug molecules. Through surface engineering of their capsids, virus-derived nanomaterials facilitate various potential applications for selective drug delivery. Viruses have significant implications in chemotherapy, gene transfer, vaccine production, immunotherapy and molecular imaging.

Which East Asian herbal medicines can decrease viral infections?

Whilst Western research for the COVID-19 crisis focuses on vaccination, in East Asia traditional herbal prescriptions are studied for SARS-CoV2 therapy. In Japan, Maoto (Ephedrae herba 4 g, Armeniacae semen 4 g, Cinnamomi cortex 3 g, and Glycyrrhizae radix 2 g, JPXVII) is used based on clinical evidence for its effect on early phase influenza (also caused by RNA viruses) comparable to that of oseltamivir. The Health Ministry of Thailand has approved Andrographis paniculata (Jap. Senshinren) extracts for treatment of COVID-19. Its combination (4 g) with Maoto, Maoto-ka-senshinren, seems most promising for the treatment of viral pandemics. In China, the official guideline for COVID-19 treatment contains TCM medications with antiviral, as well as immunmodulatory and anti-inflammatory effects such as: Qing-Fei-Pai-Du-Tang (Jap. Seihai-haidokuto) contains 21 drugs; Shufeng Jiedu Jiaonang (Bupleuri radix 8 g, Forsythiae fructus 8 g, Glycyrrhizae radix 4 g, Isatidis radix 8 g, Patriniae herba 8 g, Phragmitis rhizoma 6 g, Polygoni cuspidati rhizoma 10 g, Verbenae herba 8 g); Fufang Yuxingcao Heiji (Forsythiae fructus 0.6 g, Houttuyniae herba 6 g, Isatidis radix 1.5 g, Lonicerae flos 0.6 g, Scutellariae radix 1.5 g) first gained prominence during the 2002 SARS epidemic. With no Western medicine available, the following overview discusses efficacy and mechanisms in view of viral entry and replication of different East Asian herbal remedies for COVID-19 treatment.

Biological properties of andrographolide, an active ingredient of Andrographis Paniculata: a narrative review

Andrographolide is a labdane diterpenoid isolated from Andrographis paniculata and traditionally used in Chinese and Indian medicine. Reported effects include anti-bacterial, anti-inflammatory and anti-cancer functions. Most of the studies support the hypothesis that andrographolide supplementation stimulates immune system, so the observed effects migh in fact be secondary to the stimulation of defense reactions. As andrographolide is involved in regulation of inflammation, it is not surprising that it is also evaluated in inflammation-mediated diseases such as ulcerative colitis. Anticancer effects of the andrographolide have been tested on various cancer panels. Colon cancer, breast cancer, and head and neck carcinomas were the most investigated, followed by prostate cancer and glioblastoma. The results looked promising. However, problems with solubility and low level of active substance in natural extract leads to preparation of chemical analogs. Objective of this short review is to summarize current knowledge of the biological effects of andragrapholide. We conclude that despite documented effects and some partly characterized mechanisms of action, more research is clearly needed. At present, the doses, types of treatment and possible negative side effects are not yet established. In addition, various isolations and compound formulas have been used for treatment of various diseases, making final conclusions problematic.

Andrographolide and its derivatives: Current achievements and future perspectives

Natural product andrographolide isolated from the plant Andrographis paniculata shows a plethora of biological activities, including anti-tumor, anti-bacterial, anti-inflammation, anti-virus, anti-fibrosis, anti-obesity, immunomodulatory and hypoglycemic activities. Based on extensive chemical structural modifications, a series of andrographolide derivatives with improved bioavailability and druggability has been developed. Moreover, greater understanding of their mechanisms of action at the molecular and cellular level has been thoroughly investigated. In this review, we give an outlook for the therapeutical potential of andrographolide and its derivatives in diverse diseases and highlighted the drug design, pharmacokinetic and mechanistic studies for the past ten years, together with a brief overview of the pharmacological effects. Notably, we focused to provide a critical enlightenment of the area of andrographolide and its derivatives with the intent of indicating the future perspectives, challenges and limitations. We believe that this review paper will benefit drug discovery where andrographolide was used as a template, shed light on the identification of drug targets for andrographolide and its analogs, as well as increase our knowledge for using them for therapeutic application, including the treatment for various forms of cancers.

A review of therapeutic agents and Chinese herbal medicines against SARS-COV-2 (COVID-19)

The epidemic of pneumonia (COVID-19) caused by novel coronavirus (SARS-CoV-2) infection has been listed as a public health emergency of international concern by the World Health Organization (WHO), and its harm degree is defined as a global "pandemic". At present, the efforts of various countries focus on the rapid diagnosis and isolation of patients, as well as to find a treatment that can combat the most serious impact of the disease. The number of reported COVID-19 virus infections is still increasing. Unfortunately, no drugs or vaccines have been approved for the treatment of human coronaviruses, but there is an urgent need for in-depth research on emerging human infectious coronaviruses. Clarification transmission routes and pathogenic mechanisms, and identification of potential drug treatment targets will promote the development of effective prevention and treatment measures. In the absence of confirmed effective treatments, due to public health emergencies, it is essential to study the possible effects of existing approved antivirals drugs or Chinese herbal medicines for SARS-CoV-2. This review summarizes the epidemiological characteristics, pathogenesis, virus structure and targeting strategies of COVID-19. Meanwhile, this review also focus on the re-purposing of clinically approved drugs and Chinese herbal medicines that may be used to treat COVID-19 and provide new ideas for the discovery of small molecular compounds with potential therapeutic effects on novel COVID-19.

Aminoglycosides can be a better choice over macrolides in COVID-19 regimen: Plausible mechanism for repurposing strategy

In the current COVID-19 pandemic, prioritizing the immunity enhancers is equally important to anti-virals. Defensins are the forgotten molecules that enhance the innate immunity against various microbes. Although macrolides like azithromycin and clarithromycin etc., have been reported to act against respiratory infections but they lack the ability of immunity enhancement through defensins. The aminoglycosides were proved to have defensin mediated antiviral activity, that could enhance the immunity. So, Consideration of aminoglycosides can be a double edge sword viz., against respiratory infection as well as Immunity enhancer (along with anti-virals) for COVID-19 regimen.

Methyl-β-cyclodextrin inhibits EV-D68 virus entry by perturbing the accumulation of virus particles and ICAM-5 in lipid rafts

Enterovirus D68 (EV-D68) is a member of the Picornavirus family and a causative agent of respiratory diseases in children. The incidence of EV-D68 infection has increased worldwide in recent years. Thus far, there are no approved antiviral agents or vaccines for EV-D68. Here, we show that methyl-β-cyclodextrin (MβCD), a common drug that disrupts lipid rafts, specifically inhibits EV-D68 infection without producing significant cytotoxicity at virucidal concentrations. The addition of exogenous cholesterol attenuated the anti-EV-D68 activity of MβCD. MβCD treatment had a weak influence on the attachment of viral particles to the cell membrane but significantly inhibited EV-D68 entry into host cells. We demonstrated that EV-D68 facilitated the translocation of the viral receptor ICAM-5 to membrane rafts in infected cells. The colocalization of viral particles with ICAM-5 in lipid rafts was thoroughly abolished in cells after treatment with MβCD. Finally, we showed that MβCD inhibited the replication of isolated circulating EV-D68 strains. In summary, our results demonstrate that MβCD suppresses EV-D68 replication by perturbing the accumulation of virus particles and ICAM-5 in lipid rafts. This mechanism represents a promising strategy for drug development.

Sialoglycovirology of Lectins: Sialyl Glycan Binding of Enveloped and Non-enveloped Viruses

On the cell sur "face", sialoglycoconjugates act as receptionists that have an important role in the first step of various cellular processes that bridge communication between the cell and its environment. Loss of Sia production can cause the developmental of defects and lethality in most animals; hence, animal cells are less prone to evolution of resistance to interactions by rapidly evolved Sia-binding viruses. Obligative intracellular viruses mostly have rapid evolution that allows escape from host immunity, leading to an epidemic variant, and that allows emergence of a novel strain, occasionally leading to pandemics that cause health-social-economic problems. Recently, much attention has been given to the mutual recognition systems via sialosugar chains between viruses and their host cells and there has been rapid growth of the research field "sialoglycovirology." In this chapter, the structural diversity of sialoglycoconjugates is overviewed, and enveloped and non-enveloped viruses that bind to Sia are reviewed. Also, interactions of viral lectins-host Sia receptors, which determine viral transmission, host range, and pathogenesis, are presented. The future direction of new therapeutic routes targeting viral lectins, development of easy-to-use detection methods for diagnosis and monitoring changes in virus binding specificity, and challenges in the development of suitable viruses to use in virus-based therapies for genetic disorders and cancer are discussed.

A second open reading frame in human enterovirus determines viral replication in intestinal epithelial cells

Human enteroviruses (HEVs) of the family Picornaviridae, which comprises non-enveloped RNA viruses, are ubiquitous worldwide. The majority of EV proteins are derived from viral polyproteins encoded by a single open reading frame (ORF). Here, we characterize a second ORF in HEVs that is crucial for viral intestinal infection. Disruption of ORF2p expression decreases the replication capacity of EV-A71 in human intestinal epithelial cells (IECs). Ectopic expression of ORF2p proteins derived from diverse enteric enteroviruses sensitizes intestinal cells to the replication of ORF2p-defective EV-A71 and respiratory enterovirus EV-D68. We show that the highly conserved WIGHPV domain of ORF2p is important for ORF2p-dependent viral intestinal infection. ORF2p expression is required for EV-A71 particle release from IECs and can support productive EV-D68 infection in IECs by facilitating virus release. Our results indicate that ORF2p is a determining factor for enteric enterovirus replication in IECs.

Bypassing pan-enterovirus host factor PLA2G16

Enteroviruses are a major cause of human disease. Adipose-specific phospholipase A2 (PLA2G16) was recently identified as a pan-enterovirus host factor and potential drug target. In this study, we identify a possible mechanism of PLA2G16 evasion by employing a dual glycan receptor-binding enterovirus D68 (EV-D68) strain. We previously showed that this strain does not strictly require the canonical EV-D68 receptor sialic acid. Here, we employ a haploid screen to identify sulfated glycosaminoglycans (sGAGs) as its second glycan receptor. Remarkably, engagement of sGAGs enables this virus to bypass PLA2G16. Using cryo-EM analysis, we reveal that, in contrast to sialic acid, sGAGs stimulate genome release from virions via structural changes that enlarge the putative openings for genome egress. Together, we describe an enterovirus that can bypass PLA2G16 and identify additional virion destabilization as a potential mechanism to circumvent PLA2G16.

Recent advances on the role of host factors during non-poliovirus enteroviral infections

Non-polio enteroviruses are emerging viruses known to cause outbreaks of polio-like infections in different parts of the world with several cases already reported in Asia Pacific, Europe and in United States of America. These outbreaks normally result in overstretching of health facilities as well as death in children under the age of five. Most of these infections are usually self-limiting except for the neurological complications associated with human enterovirus A 71 (EV-A71). The infection dynamics of these viruses have not been fully understood, with most inferences made from previous studies conducted with poliovirus.Non-poliovirus enteroviral infections are responsible for major outbreaks of hand, foot and mouth disease (HFMD) often associated with neurological complications and severe respiratory diseases. The myriad of disease presentations observed so far in children calls for an urgent need to fully elucidate the replication processes of these viruses. There are concerted efforts from different research groups to fully map out the role of human host factors in the replication cycle of these viral infections. Understanding the interaction between viral proteins and human host factors will unravel important insights on the lifecycle of this groups of viruses.This review provides the latest update on the interplay between human host factors/processes and non-polio enteroviruses (NPEV). We focus on the interactions involved in viral attachment, entry, internalization, uncoating, replication, virion assembly and eventual egress of the NPEV from the infected cells. We emphasize on the virus- human host interplay and highlight existing knowledge gaps that needs further studies. Understanding the NPEV-human host factors interactions will be key in the design and development of vaccines as well as antivirals against enteroviral infections. Dissecting the role of human host factors during NPEV infection cycle will provide a clear picture of how NPEVs usurp the human cellular processes to establish an efficient infection. This will be a boost to the drug and vaccine development against enteroviruses which will be key in control and eventual elimination of the viral infections.

Andrographolide attenuates bupivacaine-induced cytotoxicity in SH-SY5Y cells through preserving Akt/mTOR activity

Background: Bupivacaine (Bup) is the most commonly used local anesthetic. However, Bup induces cytotoxicity, especially in older patients. Recent reports have indicated that andrographolide (Andro) exhibits protective effects on human neurons. Nevertheless, whether Andro can inhibit Bup-induced cytotoxicity remains unclear. As such, we investigated the effect of Andro on Bup-induced cytotoxicity of SH-SY5Y cells in the present study.

Methods: Western blotting was used to examine expression of Bax, Bcl2, active caspase 3, p-Akt, and p-mTOR in SH-SY5Y cells. In addition, ELISA was used to detect levels of total glutathione and reactive oxygen species in cells.

Results: We found that Andro attenuated Bup-induced cytotoxicity of SH-SY5Y cells. In addition, Andro inhibited Bup-induced apoptosis via downregulating the expression of Bax and active caspase 3 and upregulating the proteins Bcl2, p-Akt, and p-mTOR in SH-SY5Y cells. Moreover, Andro alleviated Bup-induced oxidative damage in SH-SY5Y cells via downregulating the level of reactive oxygen species and upregulating of the level of total glutathione. More significantly, inhibition of Akt abolished the protective effect of Andro in Bup-treated SH-SY5Y cells.

Conclusion: Our findings indicated that Andro played a neuroprotective role via preserving Akt/mTOR activity and increasing antioxidative status in Bup-treated SH-SY5Y cells. Therefore, Andro may be a potential agent for the treatment of human cytotoxicity induced by Bup.