Targeting endosomal acidification by chloroquine analogs as a promising strategy for the treatment of emerging viral diseases

An unprecedented global challenge, emerging trends and innovations in the fight against COVID-19: A comprehensive review

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a highly contagious and dangerous virus that caused the global COVID-19 pandemic in early 2020. It primarily affects the respiratory system, leading to severe illness and high rates of mortality worldwide. The virus enters the body by binding to a receptor called ACE2, which is present in specific cells of the lungs known as type 2 alveolar epithelial cells. Numerous studies have investigated the consequences of SARS-CoV-2 infection, revealing various impacts on the body. This review provides an overview of SARS-CoV-2, including its structure and how it infects cells. It also examines the different variants of concern, such as Alpha, Beta, Gamma, Delta, and the more recent Omicron variant, discussing their characteristics and the level of damage they cause. The usage of drugs to treat COVID-19 is another aspect that has been covered and compares the effectiveness and use of antiviral drugs in the treatment and its potential benefits in COVID-19 treatment. Furthermore, this review explores the consequences and abnormalities associated with SARS-CoV-2 infection, including its impact on various organs and systems in the body. And also discussing the different COVID-19 vaccines available and their effectiveness in preventing infection and reducing the severity of illness. The current review ensures the recent update of the COVID research with expert's knowledge, collection of numerous data from reliable sources and methodologies as well as update of findings based on reviews. This review also provided clear contextual explanations to aid the interpretation and application of the results. The main motto and limitation of this manuscript are to address the computational methods of drug discovery against the rapidly evolving SARS-CoV-2 virus, which has been discussed. Additionally, current computational approaches which are cost effective and can able to predict the therapeutic agents for the treatment against the virus have also been discussed.

The Influence of Lysosomal Stress on Dental Pulp Stem Cell-Derived Schwann Cells

BACKGROUND

Dysregulation of the endo-lysosomal-autophagy pathway has been identified as a critical factor in the pathology of various demyelinating neurodegenerative diseases, including peripheral neuropathies. This pathway plays a crucial role in transporting newly synthesized myelin proteins to the plasma membrane in myelinating Schwann cells, making these cells susceptible to lysosome-related dysfunctions. Nevertheless, the specific impact of lysosomal dysfunction in Schwann cells and its contribution to neurodegeneration remain poorly understood.

METHODS

We aim to mimic lysosomal dysfunction in Schwann cells using chloroquine, a lysosomal dysfunction inducer, and to monitor lysosomal leakiness, Schwann cell viability, and apoptosis over time. Additionally, due to the ethical and experimental issues associated with cell isolation and the culturing of human Schwann cells, we use human dental pulp stem cell-derived Schwann cells (DPSC-SCs) as a model in our study.

RESULTS

Chloroquine incubation boosts lysosomal presence as demonstrated by an increased Lysotracker signal. Further in-depth lysosomal analysis demonstrated an increased lysosomal size and permeability as illustrated by a TEM analysis and GAL3-LAMP1 staining. Moreover, an Alamar blue assay and Caspase-3 staining demonstrates a reduced viability and increased apoptosis, respectively.

CONCLUSIONS

Our data indicate that prolonged lysosomal dysfunction leads to lysosomal permeability, reduced viability, and eventually apoptosis in human DPSC-SCs.

Cationic dextrin nanoparticles for effective intracellular delivery of cytochrome C in cancer therapy

Intracellular protein delivery shows promise as a selective and specific approach to cancer therapy. However, a major challenge is posed by delivering proteins into the target cells. Despite the development of nanoparticle (NP)-based approaches, a versatile and biocompatible delivery system that can deliver active therapeutic cargo into the cytosol while escaping endosome degradation remains elusive. In order to overcome these challenges, a polymeric nanocarrier was prepared using cationic dextrin (CD), a biocompatible and biodegradable polymer, to encapsulate and deliver cytochrome C (Cyt C), a therapeutic protein. The challenge of endosomal escape of the nanoparticles was addressed by co-delivering the synthesized NP construct with chloroquine, which enhances the endosomal escape of the therapeutic protein. No toxicity was observed for both CD NPs and chloroquine at the concentration tested in this study. Spectroscopic investigations confirmed that the delivered protein, Cyt C, was structurally and functionally active. Additionally, the delivered Cyt C was able to induce apoptosis by causing depolarization of the mitochondrial membrane in HeLa cells, as evidenced by flow cytometry and microscopic observations. Our findings demonstrate that an engineered delivery system using CD NPs is a promising platform in nanomedicine for protein delivery applications.

An RNA replicon system to investigate promising inhibitors of feline coronavirus

Feline infectious peritonitis (FIP) is a fatal feline disease, caused by a feline coronavirus (FCoV), namely feline infectious peritonitis virus (FIPV). We produced a baby hamster kidney 21 (BHK) cell line expressing a serotype I FCoV replicon RNA with a green fluorescent protein (GFP) reporter gene (BHK-F-Rep) and used it as an in vitro screening system to test different antiviral compounds. Two inhibitors of the FCoV main protease (Mpro), namely GC376 and Nirmatrelvir, as well as the nucleoside analog Remdesivir proved to be effective in inhibiting the replicon system. Different combinations of these compounds also proved to be potent inhibitors, having an additive effect when combined. Remdesivir, GC376, and Nirmatrelvir all have a 50% cytotoxic concentration (CC50) more than 200 times higher than their half-maximal inhibitory concentrations (IC50), making them important candidates for future in vivo studies as well as clinically implemented drug candidates. In addition, results were acquired with a virus infection system, where Felis catus whole fetus 4 (Fcwf-4) cells were infected with a previously described recombinant GFP-expressing FIPV (based on the laboratory-adapted serotype I FIPV strain Black) and treated with the most promising compounds. Results acquired with the replicon system were comparable to the results acquired with the virus infection system, demonstrating that we successfully implemented the FCoV replicon system for antiviral screening. We expect that this system will greatly facilitate future screens for anti-FIPV compounds and provide a non-infectious system to study and evaluate drug-resistant mutations that may emerge in the FIPV genome.IMPORTANCEFIPV is of great significance in the cat population around the world, causing 0.3%-1.4% of feline deaths in veterinary practices (2). As there are neither effective preventive measures nor approved treatment options available, there is an urgent need to identify antiviral drugs against FIPV. Our FCoV replicon system provides a valuable tool for drug discovery in vitro. Due to the lack of cell culture systems for serotype I FCoVs (the serotype most prevalent in the feline population) (2), a different system is needed to study these viruses. A viral replicon system is a valuable tool for studying FCoVs. Overall, our results demonstrate the utility of the serotype I feline coronavirus replicon system for antiviral screening as well as to study this virus in general. We propose several compounds representing promising candidates for future clinical trials and ultimately with the potential to save cats suffering from FIP.

Poor regulation, desperation, and misinformation, a countrywide analysis of self-medication and prescription patterns in Ecuador during the COVID-19 pandemic

BACKGROUND

The rapid spread of the SARS-CoV-2 virus during the early phase of the pandemic led to an unprecedented global health crisis. Various factors have influenced self-medication practices among the general population and unsubstantiated prescribing practices among healthcare professionals.

OBJECTIVE

This study aimed to describe trends in the purchase and sale of medicines during the COVID-19 pandemic period (2020-2022) in Ecuador, by comparing them with pre-pandemic periods.

METHODS

In this study, a cross-sectional design was employed to conduct a comprehensive analysis of 28 pharmacological groups, categorized according to the Anatomical Therapeutic Chemical Classification (ATC). Utilizing an integrated drug consumption database, the study examined physician prescribing data, medicine usage, and spending levels in Ecuador during the COVID-19 pandemic. The analysis involved computing absolute differences in monthly resolution, calculating excessive expenditure in comparison to previous yearly averages, and using Defined Daily Dose (DDD) methodology for internationally comparable results. Furthermore, a correlation analysis was performed to investigate potential associations between prescribed and consumed medicines and the number of new cases and deaths.

RESULTS

In Ecuador, the average yearly expenditure among these groups prior to the pandemic (2017-2019) amounted to $150,646,206 USD, whereas during 2020 and 2021, the same groups represented a total expenditure of $228,327,210, reflecting a significant increase. The excess expenditure during this period reached 51.4%, equivalent to $77,681,004 USD. Notably, 13% of this expenditure consisted of Over the Counter (OTC) Medicines. The study also identified a remarkable surge in sales of ivermectin, which increased by 2,057%, and hydroxychloroquine, which increased by 171%, as measured by DDD.

CONCLUSIONS

This study highlights the substantial consumption of medicines by the population in Ecuador during the pandemic. It is concerning that many medications were sold without proven therapeutic indications, indicating that misinformation and desperation may have led to improper prescribing by physicians and patients resorting to ineffective drugs. Moreover, since the sale of these therapeutic drugs requires a prescription, poor regulation, and a lack of control within pharmacies likely contributed to such practices.

Poly(lactic-co-glycolic) acid nanoparticles localize in vesicles after diffusing into cells and are retained by intracellular traffic modulators

Aim: We investigated our previous finding of increased retention of poly(lactic-co-glycolic) acid nanoparticles (PLGA-NPs) with metabolic inhibitors (MI) and studied the effect of some small molecule inhibitors on PLGA-NP assimilation. Materials & methods: Intracellular PLGA-NP colocalization in the presence of MI was investigated by confocal microscopy. Intracellular retention of PLGA-NPs by some small molecules was estimated by fluorescence microscopy and flow cytometry after Pulse/Chase experiments. Results: MI caused PLGA-NP colocalization in intracellular membranous structures, mainly endosomes and lysosomes. Some small molecule inhibitors demonstrated increased intracellular PLGA-NP accumulation. Conclusion: This study elucidates the movement of PLGA-NP in cells and suggests that clinically used small molecules can reduce their extrusion by enhancing their stay within intracellular vesicles, with possible clinically beneficial consequences.

ORFV entry into host cells via clathrin-mediated endocytosis and macropinocytosis

Orf virus (ORFV), also known as infectious pustular virus, leads to an acute contagious zoonotic infectious disease. ORFV can directly contact and infect epithelial cells of skin and mucosa, causing damage to tissue cells. So far, the pathway of ORFV entry into cells is unclear. Therefore, finding the internalization pathway of ORFV will help to elucidate the cellular and molecular mechanisms of ORFV infection and invasion, which in turn will provide a certain reference for the prevention and treatment of ORFV. In the present study, chemical inhibitors were used to analyze the mechanism of ORFV entry into target cells. The results showed that the inhibitor of clathrin-mediated endocytosis could inhibit ORFV entry into cells. However, the inhibitor of caveolae-mediated endocytosis cannot inhibit ORFV entry into cells. In addition, inhibition of macropinocytosis pathway also significantly reduced ORFV internalization. Furthermore, the inhibitors of acidification and dynamin also prevented ORFV entry. However, results demonstrated that inhibitors inhibited ORFV entry but did not inhibit ORFV binding. Notably, extracellular trypsin promoted ORFV entry into cells directly, even when the endocytic pathway was inhibited. In conclusion, ORFV enters into its target cells by clathrin-mediated endocytosis and macropinocytosis, while caveolae-dependent endocytosis has little effects on this process. In addition, the entry into target cells by ORFV required an acid environment and the effect of dynamin. Meanwhile, we emphasize that broad-spectrum antiviral inhibitors and extracellular enzyme inhibitors are likely to be effective strategies for the prevention and treatment of ORFV infection.

Immunosuppression by hydroxychloroquine: mechanistic proof in in vitro experiments but limited systemic activity in a randomized placebo-controlled clinical pharmacology study

Based on its wide range of immunosuppressive properties, hydroxychloroquine (HCQ) is used for the treatment of several autoimmune diseases. Limited literature is available on the relationship between HCQ concentration and its immunosuppressive effect. To gain insight in this relationship, we performed in vitro experiments in human PBMCs and explored the effect of HCQ on T and B cell proliferation and Toll-like receptor (TLR)3/TLR7/TLR9/RIG-I-induced cytokine production. In a placebo-controlled clinical study, these same endpoints were evaluated in healthy volunteers that were treated with a cumulative dose of 2400 mg HCQ over 5 days. In vitro, HCQ inhibited TLR responses with IC50s > 100 ng/mL and reaching 100% inhibition. In the clinical study, maximal HCQ plasma concentrations ranged from 75 to 200 ng/mL. No ex vivo HCQ effects were found on RIG-I-mediated cytokine release, but there was significant suppression of TLR7 responses and mild suppression of TLR3 and TLR9 responses. Moreover, HCQ treatment did not affect B cell and T cell proliferation. These investigations show that HCQ has clear immunosuppressive effects on human PBMCs, but the effective concentrations exceed the circulating HCQ concentrations under conventional clinical use. Of note, based on HCQ's physicochemical properties, tissue drug concentrations may be higher, potentially resulting in significant local immunosuppression. This trial is registered in the International Clinical Trials Registry Platform (ICTRP) under study number NL8726.

Drug target of natural products and COVID-19: how far has science progressed?

The new coronavirus [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] that caused a viral disease with a high risk of mortality (coronavirus disease 2019) was found toward the end of 2019. This was a significant acute respiratory syndrome. In a brief period, this virus spread throughout the entire planet, causing tremendous loss of life and economic damage. The process of developing new treatments takes time, and there are presently no recognized specific treatments to treat this infection. The most promising participants, who subsequently developed into prospective leads, were dropped from the clinical research in their latter phases. Medication that has previously acquired permission may only be repurposed for use for various medical reasons following a thorough investigation for safety and effectiveness. Because there are now no effective treatments available, natural products are being used haphazardly as antiviral medications and immunity boosters. The fundamental statement that most natural compounds have powerful antiviral action does not apply to SARS-CoV-2. Middle East respiratory syndrome coronavirus and severe acute respiratory syndrome coronavirus infections are inhibited by natural treatments. According to an in silico study, the virus' nonstructural proteins, including PLpro, Mpro, and RdRp, as well as structural proteins like the spike (S) protein, have been shown to have a strong affinity for several natural products and to be inhibited by them. The virus also suggests that it is a valid candidate for therapeutic research since it utilizes the intracellular angiotensin-converting enzyme 2 receptor of the host cell. In this study, interesting targets for SARS-CoV-2 medication development are explored, as well as the antiviral properties of some well-known natural compounds.

Host Cell Targets for Unconventional Antivirals against RNA Viruses

The recent COVID-19 crisis has highlighted the importance of RNA-based viruses. The most prominent members of this group are SARS-CoV-2 (coronavirus), HIV (human immunodeficiency virus), EBOV (Ebola virus), DENV (dengue virus), HCV (hepatitis C virus), ZIKV (Zika virus), CHIKV (chikungunya virus), and influenza A virus. With the exception of retroviruses which produce reverse transcriptase, the majority of RNA viruses encode RNA-dependent RNA polymerases which do not include molecular proofreading tools, underlying the high mutation capacity of these viruses as they multiply in the host cells. Together with their ability to manipulate the immune system of the host in different ways, their high mutation frequency poses a challenge to develop effective and durable vaccination and/or treatments. Consequently, the use of antiviral targeting agents, while an important part of the therapeutic strategy against infection, may lead to the selection of drug-resistant variants. The crucial role of the host cell replicative and processing machinery is essential for the replicative cycle of the viruses and has driven attention to the potential use of drugs directed to the host machinery as therapeutic alternatives to treat viral infections. In this review, we discuss small molecules with antiviral effects that target cellular factors in different steps of the infectious cycle of many RNA viruses. We emphasize the repurposing of FDA-approved drugs with broad-spectrum antiviral activity. Finally, we postulate that the ferruginol analog (18-(phthalimide-2-yl) ferruginol) is a potential host-targeted antiviral.

Chloroquine chaos and COVID-19: Smart delivery perspectives through pH sensitive polymers/micelles and ZnO nanoparticles

The global pandemic of COVID-19 had a consequential impact on our lives. (Hydroxy)chloroquine, a well-known drug for treatment or prevention against malaria and chronic inflammatory conditions, was also used for COVID patients with reported potential efficacy. Although it was well tolerated, however in some cases, it produced severe side effects, including grave cardiac issues. The variable reports on the administration of (hydroxy)chloroquine in COVID19 patients led to chaos. This drug is a well-known zinc ionophore, besides possessing antiviral effects. Zinc ionophores augment the intracellular Zn²⁺ concentration by facilitating the zinc ions into the cells and subsequently impair virus replication. Zinc oxide nanoparticles (ZnO NPs) have been reported to possess antiviral activity. However, the adverse effects of both components are also reported. We discussed in depth their possible mechanism as antiviral and smart delivery perspectives through pH-sensitive polymers/ micelles and ZnO NPs.

Molecular Dynamics and Structural Studies of Zinc Chloroquine Complexes

Chloroquine (CQ) is a first-choice drug against malaria and autoimmune diseases. It has been co-administered with zinc against SARS-CoV-2 and soon dismissed because of safety issues. The structural features of Zn-CQ complexes and the effect of CQ on zinc distribution in cells are poorly known. In this study, state-of-the-art computations combined with experiments were leveraged to solve the structural determinants of zinc-CQ interactions in solution and the solid state. NMR, ESI-MS, and X-ray absorption and diffraction methods were combined with ab initio molecular dynamics calculations to address the kinetic lability of this complex. Within the physiological pH range, CQ binds Zn²⁺ through the quinoline ring nitrogen, forming [Zn(CQH)Cl_x(H₂O)_3-x]^(3+)-x (x = 0, 1, 2, and 3) tetrahedral complexes. The Zn(CQH)Cl₃ species is stable at neutral pH and at high chloride concentrations typical of the extracellular medium, but metal coordination is lost at a moderately low pH as in the lysosomal lumen. The pentacoordinate complex [Zn(CQH)(H₂O)₄]³⁺ may exist in the absence of chloride. This in vitro/in silico approach can be extended to other metal-targeting drugs and bioinorganic systems.

Electrochemical Response of Redox Amino Acid Encoded Fluorescence Protein for Hydroxychloroquine Sensing

The sudden rise in the demand has led to large-scale production of hydroxychloroquine (HCQ) in the global market for various diseases such as malaria, rheumatic arthritis, and systemic lupus erythematous and prophylactic treatment of early SARS-CoV-2 outbreak. Thorough monitoring of HCQ intake patients is in high demand; hence, we have developed a redox amino acid encoded fluorescent protein-based electrochemical biosensor for sensitive and selective detection of HCQ. This electrochemical biosensor is generated based on the two-electron transfer process between redox amino acid (3,4-dihydroxy-L-phenylalanine, DOPA) encoded bio-redox protein and the HCQ forms the conjugate. The DOPA residue in the bio-redox protein specifically binds with HCQ, thereby producing a remarkable electrochemical response on the glassy carbon electrode. Experimental results show that the developed biosensor selectively and sensitively detects the HCQ in spiked urine samples. The reagent-free bio-redox capacitor detects HCQ in the range of 90 nM to 4.4 µM in a solution with a detection limit of 58 nM, signal to noise ratio of 3:1, and strong anti-interference ability. Real-time screening, quantification, and relative mean recoveries of HCQ on spiked urine samples were monitored through electron shuttling using bio-redox protein and were found to be 97 to 101%. Overall, the developed bio-redox protein-based sensor has specificity, selectivity, reproducibility, and sensitivity making it potentially attractive for the sensing of HCQ and also applicable to clinical research.

Combating the Progression of Novel Coronavirus SARS-CoV-2 Infectious Disease: Current State and Future Prospects in Molecular Diagnostics and Drug Discovery

A highly infectious and life-threatening virus was first reported in Wuhan, China, in late 2019, and it rapidly spread all over the world. This novel virus belongs to the coronavirus family and is associated with severe acute respiratory syndrome (SARS), causing respiratory disease known as COVID-19. In March 2020, WHO has declared the COVID-19 outbreak a global pandemic. Its morbidity and mortality rates are swiftly rising day by day, with the situation becoming more severe and fatal for the comorbid population. Many COVID-19 patients are asymptomatic, but they silently spread the infection. There is a need for proper screening of infected patients to prevent the epidemic transmission of disease and for early curative interventions to reduce the risk of developing severe complications from COVID-19. To date, the diagnostic assays are of two categories, molecular detection of viral genetic material by real-time RTpolymerase chain reaction and serological test, which relies on detecting antiviral antibodies. Unfortunately, there are no effective prophylactics and therapeutics available against COVID-19. However, a few drugs have shown promising antiviral activity against it, and these presently are being referred for clinical trials, albeit FDA has issued an Emergency Use Authorization (EUA) for the emergency use of a few drugs for SARSCoV- 2 infection. This review provides an insight into current progress, challenges and future prospects of laboratory detection methods of COVID-19, and highlights the clinical stage of the major evidence-based drugs/vaccines recommended against the novel SARS-CoV-2 pandemic virus.

Surfactant-free air bubble flotation-coagulation for the rapid purification of chloroquine

A simple and rapid separation method based on surfactant-free air bubble flotation and coagulation was designed for the purification of chloroquine (CQ) from its crude product. An open glass column having a sintered glass filter (for column chromatography) was used as a flotation vessel. The flotation was conducted by pouring the crude CQ into the aqueous solution containing 0.1% (v/v) of 2-propanol followed by feeding air through the glass filter to generate air bubbles. At pH 12, CQ was enriched into the foam temporary generating on the surface of water to form the coagulates within 90 s after the start of the air bubble flotation. On the other hand, reactants; 4,7-dichloroquinoline and 4-amino-1-diethylaminopentane, as well as generated impurities remained in the bulk aqueous solution. The result of dynamic surface tension measurement indicated that CQ molecules selectively adsorbed on the air-water interface and the coagulates more strongly adsorbed the interface. Adsorption and coagulation of CQ molecules on the air-water interface were also reproduced in the calculation results of a molecular dynamic simulation. The coagulates were collected from the surface of water by suction and then poured into another flotation vessel for conducting repeated separation. The time required for the respective separation process including air bubble flotation and collection by suction was within 5 min. After three-times separation, highly purified (> 99.0%) CQ was obtained with a yield of 72 ± 8%. The amounts of reactants and other impurities reduced into undetectable levels.

Insight into the role of clathrin-mediated endocytosis inhibitors in SARS-CoV-2 infection

Emergence of SARS-CoV-2 variants warrants sustainable efforts to upgrade both the diagnostic and therapeutic protocols. Understanding the details of cellular and molecular basis of the virus-host cell interaction is essential for developing variant-independent therapeutic options. The internalization of SARS-CoV-2, into lung epithelial cells, is mediated by endocytosis, especially clathrin-mediated endocytosis (CME). Although vaccination is the gold standard strategy against viral infection, selective inhibition of endocytic proteins, complexes, and associated adaptor proteins may present a variant-independent therapeutic strategy. Although clathrin and/or dynamins are the most important proteins involved in CME, other endocytic mechanisms are clathrin and/or dynamin independent and rely on other proteins. Moreover, endocytosis implicates some subcellular structures, like plasma membrane, actin and lysosomes. Also, physiological conditions, such as pH and ion concentrations, represent an additional factor that mediates these events. Accordingly, endocytosis related proteins are potential targets for small molecules that inhibit endocytosis-mediated viral entry. This review summarizes the potential of using small molecules, targeting key proteins, participating in clathrin-dependent and -independent endocytosis, as variant-independent antiviral drugs against SARS-CoV-2 infection. The review takes two approaches. The first outlines the potential role of endocytic inhibitors in preventing endocytosis-mediated viral entry and its mechanism of action, whereas in the second computational analysis was implemented to investigate the selectivity of common inhibitors against endocytic proteins in SARS-CoV-2 endocytosis. The analysis revealed that remdesivir, methyl-β-cyclodextrin, rottlerin, and Bis-T can effectively inhibit clathrin, HMG-CoA reductase, actin, and dynamin I GTPase and are more potent in inhibiting SARS-CoV-2 than chloroquine. CME inhibitors for SARS-CoV-2 infection remain understudied.

Recognition and movement of polystyrene nanoplastics in fish cells

Although nanoplastics are being increasingly scrutinized, little is known about their kinetic behavior in living organisms, especially in cellular systems. Herein, nonspecific interactions of three polystyrene nanoplastics (pristine-PS, NH₂-PS, and COOH-PS, with size range of 90-100 nm and at concentrations of 0-100 μg mL^-1) with zebrafish cells were quantified for their cellular uptake and exocytosis. Cell uptake of nanoplastics reached a peak within 2 h and then decreased. The overall nanoplastics uptake was dominated by PS-particle internalization. The estimated uptake rate was comparable among the different types of PS (pristine-PS, NH₂-PS, and COOH-PS), but the uptake capacity was related to their functionality. The clathrin-mediated and caveolae-mediated pathways were mainly involved in the uptake of the three nanoplastics. The internalized PS-particles were initially delivered to the cytoplasm but then transported to lysosomes using energy. Meanwhile, these PS particles were released by the cells via energy-free penetration and energy-dependent lysosomal exocytosis. PS-particles were removed by the cells at a relatively slow rate, and the estimated retention half-lives of these PS-particles were 10.1 h, 12.0 h and 15.1 h for pristine-PS, NH₂-PS and COOH-PS particles, respectively, in fish cells based on our kinetic measurements. Intracellular trajectory modeling of nanoplastics movement is critical for the environmental and human health risk assessment.

Monotherapy versus polytherapy of enoxaparin and hydroxychloroquine for the treatment of COVID-19: A randomized controlled clinical trial

Objectives

The current study aims to assess the efficacy and safety of Enoxaparin and hydroxychloroquine (HCQ) used as monothrapy or polytherapy versus standard care alone in Coronavirus 2019 (COVID-19) infected patients.

Methods

The current study included two hundred patients with laboratory confirmed COVID-19 infection. Patients admitted to hospital were randomly allocated into four groups: group I: received standard COVID-19 therapy, group II: received Enoxaparin 40mg/day subcutaneously (SC) plus standard therapy, group III: received 400 mg/day HCQ plus standard therapy & group IV: received a combination of 400 mg/day HCQ and Enoxaparin plus standard COVID-19 therapy. The disease progression was evaluated by duration to a negative polymerase chain reaction (PCR), length of hospital or Intensive Care Unit (ICU) stay, and mortality rate. The safety of treatments was evaluated by measuring adverse effects.

Results

The length of hospital stay, ICU admission and mortality were significantly decreased in Enoxaparin plus standard COVID-19 therapy group versus other groups.

Conclusion

These findings suggest that Enoxaparin was safe, effective, and well tolerated and has a role in decreasing the progression of the disease and its complications while HCQ did not discover any evidence of extra therapeutic benefits.

Prophylactic and therapeutic potential of selected immunomodulatory agents from Ayurveda against coronaviruses amidst the current formidable scenario: an in silico analysis

There is currently a dearth of specific therapies to treat respiratory infections caused by the three related species of coronaviruses viz. SARS-CoV-2, SARS-CoV and MERS-CoV. Prevention from disease is currently the safest and most convenient alternative available. The present study aimed to evaluate the preventive and therapeutic effect of fifteen phytoconstituents from medicinal plants of Ayurveda against coronaviruses by in silico screening. All the phytoconstituents exhibited rapid GI absorption and bioavailability and most of them had no toxicity versus reference drug chloroquine. BAS analyses revealed that most of the phytocomponents had favorable bioactivity scores towards biological target proteins. Principal component analysis revealed that most of the phytoconstituents fell close to chloroquine in 3D projection of chemical space. Affinity of phytoconstituents towards SARS-CoV-2 spike protein-human ACE2 complex decreased as isomeldenin > tinosporaside > EGCG whereas in case of unbound ACE2, the strength of binding followed the order isomeldenin > tinosporaside > ellagic acid. Towards SARS-CoV-2 main and papain-like proteases, the affinity decreased as isomeldenin > EGCG > tinosporaside and EGCG > tinosporaside > isomeldenin, respectively. Most phytoconstituents displayed significant binding kinetics to the selected protein targets than chloroquine. SAR analysis revealed that isomeldenin, tinosporaside, EGCG and ellagic acid bind to viral spike glycoproteins via H-bond, Pi-Pi, Pi-sigma and Pi-alkyl type interactions. Molecular dynamics simulation of isomeldenin and EGCG with SARS-CoV and SARS-CoV-2 spike glycoproteins exhibited low deviations throughout the 100 ns simulation indicating good stability and compactness of the protein-ligand complexes. Thus, the above four phytoconstituents have the potential to emerge as prophylactic and therapeutic agents against coronaviruses if investigated further in vitro and in vivo.

Antiviral effect of lysosomotropic disaccharide trehalose on porcine hemagglutinating encephalomyelitis virus, a highly neurotropic betacoronavirus

Many members of the genus Betacoronavirus are neurotropic viruses that frequently cause serious harm to humans or animals, including highly neurotropic porcine hemagglutinating encephalomyelitis virus (PHEV). Nevertheless, very few approved treatments exist to combat these viruses. Lysosomotropic trehalose, a widely used, nontoxic, natural disaccharide that can traverse the blood-brain barrier, has been proposed as a potential antiviral agent for use in prevention or treatment of betacoronavirus-associated infections. The purpose of this study was to determine if trehalose could inhibit PHEV infection of cells of a mouse central nervous system-derived neuroblastoma cell line in vitro or brain cells in vivo. Our results demonstrated that treatment of PHEV-infected mouse neuroblastoma cells and mice with trehalose reduced viral replication and that these trehalose antiviral effects were dependent on expression of lysosomal protein progranulin. Collectively, these results indicated that trehalose holds promise as a new antiviral agent for use in controlling neurotropic betacoronavirus infections.

The Diphtheria Toxin Translocation Domain Impairs Receptor Selectivity in Cancer Cell-Targeted Protein Nanoparticles

Protein-based materials intended as nanostructured drugs or drug carriers are progressively gaining interest in nanomedicine, since their structure, assembly and cellular interactivity can be tailored by recruiting functional domains. The main bottleneck in the development of deliverable protein materials is the lysosomal degradation that follows endosome maturation. This is especially disappointing in the case of receptor-targeted protein constructs, which, while being highly promising and in demand in precision medicines, enter cells via endosomal/lysosomal routes. In the search for suitable protein agents that might promote endosome escape, we have explored the translocation domain (TD) of the diphtheria toxin as a functional domain in CXCR4-targeted oligomeric nanoparticles designed for cancer therapies. The pharmacological interest of such protein materials could be largely enhanced by improving their proteolytic stability. The incorporation of TD into the building blocks enhances the amount of the material detected inside of exposed CXCR4⁺ cells up to around 25-fold, in absence of cytotoxicity. This rise cannot be accounted for by endosomal escape, since the lysosomal degradation of the new construct decreases only moderately. On the other hand, a significant loss in the specificity of the CXCR4-dependent cellular penetration indicates the unexpected role of the toxin segment as a cell-penetrating peptide in a dose-dependent and receptor-independent fashion. These data reveal that the diphtheria toxin TD displayed on receptor-targeted oligomeric nanoparticles partially abolishes the exquisite receptor specificity of the parental material and it induces nonspecific internalization in mammalian cells.

Potential use of the S-protein-Angiotensin converting enzyme 2 binding pathway in the treatment of coronavirus disease 2019

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes coronavirus disease 2019 (COVID-19), infects humans through a strong interaction between the viral spike protein (S-protein) and angiotensin converting enzyme 2 (ACE2) receptors on the cell surface. The infection of host lung cells by SARS-CoV-2 leads to clinical symptoms in patients. However, ACE2 expression is not restricted to the lungs; altered receptors have been found in the nasal and oral mucosa, vessel, brain, pancreas, gastrointestinal tract, kidney, and heart. The future of COVID-19 is uncertain, however, new viral variants are likely to emerge. The SARS-CoV-2 Omicron variant has a total of 50 gene mutations compared with the original virus; 15 of which occur in the receptor binding domain (RBD). The RBD of the viral S-protein binds to the human ACE2 receptor for viral entry. Mutations of the ACE2-RBD interface enhance tight binding by increasing hydrogen bond interactions and expanding the accessible surface area. Extracorporeal membrane oxygenation, hyperbaric oxygen, and aggressive dialysis for the treatment of COVID-19 have shown various degrees of clinical success. The use of decoy receptors based on the ACE2 receptor as a broadly potent neutralizer of SARS-CoV-2 variants has potential as a therapeutic mechanism. Drugs such as 3E8 could block binding of the S1-subunit to ACE2 and restrict the infection of ACE2-expressing cells by a variety of coronaviruses. Here, we discuss the development of ACE2-targeted strategies for the treatment and prevention of COVID-19.

Drug-induced liver injury in COVID-19 treatment: Incidence, mechanisms and clinical management

The COVID-19 outbreak triggered a serious and potentially lethal pandemic, resulting in massive health and economic losses worldwide. The most common clinical manifestations of COVID-19 patients are pneumonia and acute respiratory distress syndrome, with a variety of complications. Multiple organ failure and damage, ultimately leading to patient death, are possible as a result of medication combinations, and this is exemplified by DILI. We hope to summarize DILI caused by the antiviral drugs favipiravir, remdesivir, lopinavir/ritonavir, and hydroxychloroquine in COVID-19 patients in this review. The incidence of liver injury in the treatment of COVID-19 patients was searched on PubMed to investigate DILI cases. The cumulative prevalence of acute liver injury was 23.7% (16.1%-33.1%). We discuss the frequency of these events, potential mechanisms, and new insights into surveillance strategies. Furthermore, we also describe medication recommendations aimed at preserving DILI caused by treatment in COVID-19 patients.

Biologic Functions of Hydroxychloroquine in Disease: From COVID-19 to Cancer

Chloroquine (CQ) and Hydroxychloroquine (HCQ), initially utilized in the treatment of malaria, have now developed a long list of applications. Despite their clinical relevance, their mechanisms of action are not clearly defined. Major pathways by which these agents are proposed to function include alkalinization of lysosomes and endosomes, downregulation of C-X-C chemokine receptor type 4 (CXCR4) expression, high-mobility group box 1 protein (HMGB1) inhibition, alteration of intracellular calcium, and prevention of thrombus formation. However, there is conflicting data present in the literature. This is likely the result of the complex overlapping pathways between these mechanisms of action that have not previously been highlighted. In fact, prior research has focused on very specific portions of particular pathways without describing these in the context of the extensive CQ/HCQ literature. This review summarizes the detailed data regarding CQ/HCQ's mechanisms of action while also providing insight into the overarching themes. Furthermore, this review provides clinical context to the application of these diverse drugs including their role in malaria, autoimmune disorders, cardiovascular disease, thrombus formation, malignancies, and viral infections.

Hydroxychloroquine for treatment of COVID-19 patients: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

We performed a systematic review of the literature and meta-analysis on the efficacy and safety of hydroxychloroquine to treat COVID-19 patients.

METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and LILACS (January 2019 to March 2021) for patients aged 18 years or older, who had COVID-19 and were treated with hydroxychloroquine versus placebo or standard of care. We also searched the WHO Clinical Trials Registry for ongoing and recently completed studies, and the reference lists of selected articles and reviews for possible relevant studies, with no restrictions regarding language or publication status. Random-effects models were used to obtain pooled mean differences of treatment effect on mortality, and serious adverse effects between hydroxychloroquine and the Control Group (standard of care or placebo); heterogeneity was assessed using the I2 and the Cochran´s Q statistic.

RESULTS

Nine studies met the inclusion criteria and were included in the meta-analysis. There was no significant difference in mortality rate between patients treated with hydroxychloroquine compared to standard of care or placebo (16.7% versus 18.5%; pooled risk ratio 1.09; 95% confidence interval: 0.99-1.19). Also, the rate of serious adverse effects was similar between both Groups, Hydroxychloroquine and Control (3.7% versus 2.9%; pooled risk ratio 1.22; 95% confidence interval: 0.76-1.96).

CONCLUSION

Hydroxychloroquine is not efficacious in reducing mortality of COVID-19 patients.

PROSPERO DATABASE REGISTRATION

(www.crd.york.ac.uk/prospero) under number CRD42020197070.

LRP1-Mediated Endocytosis May Be the Main Reason for the Difference in Cytotoxicity of Curcin and Curcin C on U2OS Osteosarcoma Cells

Curcin and Curcin C, both of the ribosome-inactivating proteins of Jatropha curcas, have apparent inhibitory effects on the proliferation of osteosarcoma cell line U20S. However, the inhibitory effect of the latter is 13-fold higher than that of Curcin. The mechanism responsible for the difference has not been studied. This work aimed to understand and verify whether there are differences in entry efficiency and pathway between them using specific endocytosis inhibitors, gene silencing, and labeling techniques such as fluorescein isothiocyanate (FITC) labeling. The study found that the internalization efficiency of Curcin C was twice that of Curcin for U2OS cells. More than one entering pathway was adopted by both of them. Curcin C can enter U2OS cells through clathrin-dependent endocytosis and macropinocytosis, but clathrin-dependent endocytosis was not an option for Curcin. The low-density lipoprotein receptor-related protein 1 (LRP1) was found to mediate clathrin-dependent endocytosis of Curcin C. After LRP1 silencing, there was no significant difference in the 50% inhibitory concentration (IC₅₀) and endocytosis efficiency between Curcin and Curcin C on U2OS cells. These results indicate that LRP1-mediated endocytosis is specific to Curcin C, thus leading to higher U2OS endocytosis efficiency and cytotoxicity than Curcin.

Can natural products modulate cytokine storm in SARS-CoV2 patients?

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Immune reaction CoV2 can cause uncontrolled systemic inflammatory responses called cytokine storm.

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Medicinal plants and their secondary metabolites are potential modulators of cytokine storm.

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Secondary metabolites modulate inflammatory signaling associated with CoV2.

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The potential applicability of natural products against CoV2 need to be evaluated in strictly defined clinical research.

Currently, the number of cases and deaths of SARS-CoV2, especially among the chronic disease groups, due to aggressive SARS-CoV2 infection is increasing day by day. Various infections, particularly viral ones, cause a cytokine storm resulting in shortness of breath, bleeding, hypotension, and ultimately multi-organ failure due to over-expression of certain cytokines and necrosis factors. The most prominent clinical feature of SARS-CoV2 is the presence of elevated proinflammatory cytokines in the serum of patients with SARS-CoV2. Severe cases exhibit higher levels of cytokines, leading to a “cytokine storm” that further increases disease severity and causes acute respiratory distress syndrome, multiple organ failure, and death. Therefore, targeted cytokine production could be a potential therapeutic option for patients severely infected with SARS-CoV2.

Given the current scenario, great scientific progress has been made in understanding the disease and its forms of treatment. Because of natural ingredients properties, they have the potential to be used as potential agents with the ability to modulate immune responses. Moreover, they can be used safely because they have no toxic effects, are biodegradable and biocompatible. However, these natural substances can continue to be used in the development of new therapies and vaccines.

Finally, the aim and approach of this review article is to highlight current research on the possible use of natural products with promising potential as immune response activators. Moreover, consider the expected use of natural products when developing potential therapies and vaccines.

Engineered Macrophage-Membrane-Coated Nanoparticles with Enhanced PD-1 Expression Induce Immunomodulation for a Synergistic and Targeted Antiglioblastoma Activity

Glioblastoma (GBM), the most common subtype of malignant gliomas, is characterized by aggressive infiltration, high malignancy, and poor prognosis. The frustrating anti-GBM outcome of conventional therapeutics is due to the immunosuppressive milieu, in addition to the formidable obstacle of the blood-brain barrier (BBB). Combination therapy with an immune checkpoint blockade (ICB) has emerged as a critical component in the treatment of GBM. Here, we report an engineered macrophage-membrane-coated nanoplatform with enhanced programmed cell death-1 (PD-1) expression (PD-1-MM@PLGA/RAPA). Using both in vitro and in vivo GBM models, we demonstrate that PD-1-MM@PLGA/RAPA can efficiently traverse across the BBB in response to the tumor microenvironment (TME) recruitment with nanoparticles accumulating at the tumor site. Furthermore, we show a boosted immune response as a result of enhancing CD8⁺ cytotoxic T-lymphocyte (CTL) infiltration. Together we provide a new nanoplatform for enhancing ICB in combination with conventional chemotherapy for GBM and many other cancers.

Antiparasitic Drugs against SARS-CoV-2: A Comprehensive Literature Survey

More than two years have passed since the viral outbreak that led to the novel infectious respiratory disease COVID-19, caused by the SARS-CoV-2 coronavirus. Since then, the urgency for effective treatments resulted in unprecedented efforts to develop new vaccines and to accelerate the drug discovery pipeline, mainly through the repurposing of well-known compounds with broad antiviral effects. In particular, antiparasitic drugs historically used against human infections due to protozoa or helminth parasites have entered the main stage as a miracle cure in the fight against SARS-CoV-2. Despite having demonstrated promising anti-SARS-CoV-2 activities in vitro, conflicting results have made their translation into clinical practice more difficult than expected. Since many studies involving antiparasitic drugs are currently under investigation, the window of opportunity might be not closed yet. Here, we will review the (controversial) journey of these old antiparasitic drugs to combat the human infection caused by the novel coronavirus SARS-CoV-2.

Cell deaths: Involvement in the pathogenesis and intervention therapy of COVID-19

The current pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has dramatically influenced various aspects of the world. It is urgent to thoroughly study pathology and underlying mechanisms for developing effective strategies to prevent and treat this threatening disease. It is universally acknowledged that cell death and cell autophagy are essential and crucial to maintaining host homeostasis and participating in disease pathogenesis. At present, more than twenty different types of cell death have been discovered, some parts of which have been fully understood, whereas some of which need more investigation. Increasing studies have indicated that cell death and cell autophagy caused by coronavirus might play an important role in virus infection and pathogenicity. However, the knowledge of the interactions and related mechanisms of SARS-CoV-2 between cell death and cell autophagy lacks systematic elucidation. Therefore, in this review, we comprehensively delineate how SARS-CoV-2 manipulates diverse cell death (including apoptosis, necroptosis, pyroptosis, ferroptosis, and NETosis) and cell autophagy for itself benefits, which is simultaneously involved in the occurrence and progression of COVID-19, aiming to provide a reasonable basis for the existing interventions and further development of novel therapies.

SARS-CoV-2: Molecular Structure, Pathogenesis, Potential Therapeutic Targets, and Immune Response of the Infected Subject

Background

The pathogenic mechanisms and immune response of COVID-19 are far from clear. Through a documentary review of literature, the authors describe virological and molecular aspects of SARS-CoV-2, the intimate mechanisms of cell infection, and potential therapeutic targets. They also analyze the characteristics of immune response of the infected subject.

Objectives

Objectives of this study are to describe the state of knowledge on virological data, molecular and physiopathogenic mechanisms of SARS-CoV-2, with a view to a better understanding of the therapeutic targets, as well as the immune response of the infected subject. Methodology. This documentary review is a compilation of several meta-analyses, consistent with the methodology described in the PRISMA statement on literature data on SARS-CoV-2, published between March 22 and August 14, 2020 (Moher et al.). The search engines used for the selection of articles were as follows: PubMed, Google Scholar, Global Health, and WHO reports. Papers of interest were those addressing virological and molecular data on SARS-CoV-2, therapeutic aspects of COVID-19, and immunity of the infected subject. Of the 617 eligible papers, 417 could be retained after removing the duplicates. Ultimately, only 50 articles were retained for final evaluation. The data collected allowed the development of a two-armed model around the physiopathological aspects and potential therapeutic targets, as well as aspects of host immunity, respectively. The model was then compared to data from the HIV literature.

Conclusion

Reported data could contribute to a better understanding of molecular mechanisms of cellular infection by SARS-CoV-2 as well as to a more easy explanation of the action of pharmacological agents used for the treatment, while elucidating intimate mechanisms of the immunity of infected subject.

Targeting Selective Autophagy as a Therapeutic Strategy for Viral Infectious Diseases

Autophagy is an evolutionarily conserved lysosomal degradation system which can recycle multiple cytoplasmic components under both physiological and stressful conditions. Autophagy could be highly selective to deliver different cargoes or substrates, including protein aggregates, pathogenic proteins or superfluous organelles to lysosome using a series of cargo receptor proteins. During viral invasion, cargo receptors selectively target pathogenic components to autolysosome to defense against infection. However, viruses not only evolve different strategies to counteract and escape selective autophagy, but also utilize selective autophagy to restrict antiviral responses to expedite viral replication. Furthermore, several viruses could activate certain forms of selective autophagy, including mitophagy, lipophagy, aggrephagy, and ferritinophagy, for more effective infection and replication. The complicated relationship between selective autophagy and viral infection indicates that selective autophagy may provide potential therapeutic targets for human infectious diseases. In this review, we will summarize the recent progress on the interplay between selective autophagy and host antiviral defense, aiming to arouse the importance of modulating selective autophagy as future therapies toward viral infectious diseases.

Roles of Endomembrane Alkali Cation/Proton Exchangers in Synaptic Function and Neurodevelopmental Disorders

Endomembrane alkali cation (Na⁺, K⁺)/proton (H⁺) exchangers (eNHEs) are increasingly associated with neurological disorders. These eNHEs play integral roles in regulating the luminal pH, processing, and trafficking of cargo along the secretory (Golgi and post-Golgi vesicles) and endocytic (early, recycling, and late endosomes) pathways, essential regulatory processes vital for neuronal development and plasticity. Given the complex morphology and compartmentalization of multipolar neurons, the contribution of eNHEs in maintaining optimal pH homeostasis and cargo trafficking is especially significant during periods of structural and functional development and remodeling. While the importance of eNHEs has been demonstrated in a variety of non-neuronal cell types, their involvement in neuronal function is less well understood. In this review, we will discuss their emerging roles in excitatory synaptic function, particularly as it pertains to cellular learning and remodeling. We will also explore their connections to neurodevelopmental conditions, including intellectual disability, autism, and attention deficit hyperactivity disorders.

SARS-CoV-2: An Overview of the Genetic Profile and Vaccine Effectiveness of the Five Variants of Concern

With the onset of the COVID-19 pandemic, enormous efforts have been made to understand the genus SARS-CoV-2. Due to the high rate of global transmission, mutations in the viral genome were inevitable. A full understanding of the viral genome and its possible changes represents one of the crucial aspects of pandemic management. Structural protein S plays an important role in the pathogenicity of SARS-CoV-2, mutations occurring at this level leading to viral forms with increased affinity for ACE2 receptors, higher transmissibility and infectivity, resistance to neutralizing antibodies and immune escape, increasing the risk of infection and disease severity. Thus, five variants of concern are currently being discussed, Alpha, Beta, Gamma, Delta and Omicron. In the present review, a comprehensive summary of the following critical aspects regarding SARS-CoV-2 has been made: (i) the genomic characteristics of SARS-CoV-2; (ii) the pathological mechanism of transmission, penetration into the cell and action on specific receptors; (iii) mutations in the SARS-CoV-2 genome; and (iv) possible implications of mutations in diagnosis, treatment, and vaccination.

Combined Therapy with Ivermectin and Doxycycline can effectively alleviate the Cytokine Storm of COVID-19 Infection amid Vaccination Drive: A Narrative Review

An unprecedented global health crisis has developed due to the emergence of the mysterious coronavirus-2 of the severe acute respiratory syndrome, which has resulted in millions of deaths around the globe, as no therapy could control the ‘cytokine storm’. Consequently, many vaccines have been developed and several others are being developed for this infection. Although most of the approved vaccines have been highly effective, many developing, and economically poor countries are still deprived of vaccination against SARS-CoV-2 due to the unequal distribution of vaccines worldwide. Furthermore, the uncertainty about the effectiveness of the available vaccines against the emerging mutants and variants also remains a matter of concern. Due to the multistep pathogenesis and unique features, combination therapy using safe immunomodulatory and antiviral drugs should be considered as the most effective and acceptable therapeutic regimen for this infection. Based on a thorough assessment of the literature, it was determined that it would be interesting to study the therapeutic potential of ivermectin and doxycycline, given their roles in several biological pathways involved in SARS CoV-2 pathogenesis. Following that, a comprehensive literature search was undertaken using Scopus, Web of Science, and Pubmed, depending on the inclusion and exclusion criteria. The present study provides a mechanism and comprehensive report, highlighting the role of combined therapy with ivermectin and doxycycline in alleviating the ‘cytokine storm’ of COVID-19 infection.

Divalent Metal Ions Boost Effect of Nucleic Acids Delivered by Cell-Penetrating Peptides

Cell-penetrating peptides (CPPs) are promising tools for the transfection of various substances, including nucleic acids, into cells. The aim of the current work was to search for novel safe and effective approaches for enhancing transfection efficiency of nanoparticles formed from CPP and splice-correcting oligonucleotide (SCO) without increasing the concentration of peptide. We analyzed the effect of inclusion of calcium and magnesium ions into nanoparticles on CPP-mediated transfection in cell culture. We also studied the mechanism of such transfection as well as its efficiency, applicability in case of different cell lines, nucleic acid types and peptides, and possible limitations. We discovered a strong positive effect of these ions on transfection efficiency of SCO, that translated to enhanced synthesis of functional reporter protein. We observed significant changes in intracellular distribution and trafficking of nanoparticles formed by the addition of the ions, without increasing cytotoxicity. We propose a novel strategy for preparing CPP-oligonucleotide nanoparticles with enhanced efficiency and, thus, higher therapeutic potential. Our discovery may be translated to primary cell cultures and, possibly, in vivo studies, with the aim of increasing CPP-mediated transfection efficiency and the likelihood of using CPPs in clinics.

The “Invisible Enemy” SARS-CoV-2: Viral Spread and Drug Treatment

Nowadays, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has become the main subject of the scientific medical world and all World Organizations, causing millions of deaths worldwide. In this review, we have highlighted the context of the Coronavirus disease 2019 (COVID-19) pandemic, how the virus spreads, the symptoms and complications that may occur, and, especially, the drug treatment of viral infection, with emphasis on monoclonal antibodies. While well-known strains such as Alpha, Beta, Gamma, and, especially, Delta have shown an accelerated transmission among the population, the new Omicron variant (discovered on 24 November 2021) indicates more significant infectiousness and the poor efficacy of monoclonal antibody therapy due to mutations on the spike protein receptor-binding domain. With these discoveries, the experiments began, the first being in silico and in vitro, but these are not enough, and in vivo experiments are needed to see exactly the cause of neutralization of the action of these drugs. Following the documentation of the latest medical and scientific research, it has been concluded that there are many chemical molecules that have the potential to treat SARS-CoV-2 infection, but more detailed clinical trials are needed for their use in therapy. In addition, it is important to consider the structure of the viral strain in the administration of treatment.

SARS-CoV-2-host cell surface interactions and potential antiviral therapies

In this review, we reveal the latest developments at the interface between SARS-CoV-2 and the host cell surface. In particular, we evaluate the current and potential mechanisms of binding, fusion and the conformational changes of the spike (S) protein to host cell surface receptors, especially the human angiotensin-converting enzyme 2 (ACE2) receptor. For instance, upon the initial attachment, the receptor binding domain of the S protein forms primarily hydrogen bonds with the protease domain of ACE2 resulting in conformational changes within the secondary structure. These surface interactions are of paramount importance and have been therapeutically exploited for antiviral design, such as monoclonal antibodies. Additionally, we provide an insight into novel therapies that target viral non-structural proteins, such as viral RNA polymerase. An example of which is remdesivir which has now been approved for use in COVID-19 patients by the US Food and Drug Administration. Establishing further understanding of the molecular details at the cell surface will undoubtably aid the development of more efficacious and selectively targeted therapies to reduce the burden of COVID-19.

Association between oral antimalarial medication administration and mortality among patients with Ebola virus disease: a multisite cohort study

BACKGROUND

Empiric antimalarial treatment is a component of protocol-based management of Ebola virus disease (EVD), yet this approach has limited clinical evidence for patient-centered benefits.

METHODS

This retrospective cohort study evaluated the association between antimalarial treatment and mortality among patients with confirmed EVD. The data was collected from five International Medical Corps operated Ebola Treatment Units (ETUs) in Sierra Leone and Liberia from 2014 through 2015. The standardized protocol used for patient care included empiric oral treatment with combination artemether and lumefantrine, twice daily for three days; however, only a subset of patients received treatment due to resource variability. The outcome of interest was mortality, comparing patients treated with oral antimalarials within 48-h of admission to those not treated. Analysis was conducted with logistic regression to generate adjusted odds ratios (aORs). Multivariable analyses controlled for ETU country, malaria rapid diagnostic test result, age, EVD cycle threshold value, symptoms of bleeding, diarrhea, dysphagia and dyspnea, and additional standard clinical treatments.

RESULTS

Among the 424 cases analyzed, 376 (88.7%) received early oral antimalarials. Across all cases, mortality occurred in 57.5% (244). In comparing unadjusted mortality prevalence, early antimalarial treated cases yielded 55.1% mortality versus 77.1% mortality for those untreated (p = 0.005). Multivariable analysis demonstrated evidence of reduced aOR for mortality with early oral antimalarial treatment versus non-treatment (aOR = 0.34, 95% Confidence Interval: 0.12, 0.92, p = 0.039).

CONCLUSION

Early oral antimalarial treatment in an EVD outbreak was associated with reduced mortality. Further study is warranted to investigate this association between early oral antimalarial treatment and mortality in EVD patients.

In Vitro and In Vivo Analysis of Extracellular Vesicle-Mediated Metastasis Using a Bright, Red-Shifted Bioluminescent Reporter Protein

Cancer cells produce heterogeneous extracellular vesicles (EVs) as mediators of intercellular communication. This study focuses on a novel method to image EV subtypes and their biodistribution in vivo. A red-shifted bioluminescence resonance energy transfer (BRET) EV reporter is developed, called PalmReNL, which allows for highly sensitive EV tracking in vitro and in vivo. PalmReNL enables the authors to study the common surface molecules across EV subtypes that determine EV organotropism and their functional differences in cancer progression. Regardless of injection routes, whether retro-orbital or intraperitoneal, PalmReNL positive EVs, isolated from murine mammary carcinoma cells, localized to the lungs. The early appearance of metastatic foci in the lungs of mammary tumor-bearing mice following multiple intraperitoneal injections of the medium and large EV (m/lEV)-enriched fraction derived from mammary carcinoma cells is demonstrated. In addition, the results presented here show that tumor cell-derived m/lEVs act on distant tissues through upregulating LC3 expression within the lung.

Antiviral, Anticancer and Hypotensive Potential of Diphyllin Glycosides and their Mechanisms of Action

Diphyllin glycosides (DG) are the type of arylnaphthalene lignans isolated from different plants and their synthetic derivatives have shown effective antiviral, cytotoxic, hypotensive and diuretic effects at very low concentrations similar to standard drugs that are under clinical use. The biological activities of the DG interfere with signaling pathways of viral infection and cancer induction. The sugar moieties of DG enhance bioavailability and pharmacological activities. The promising results of DG at nanomolar concentrations under in vitro and in vivo conditions should be explored further with clinical trials to determine its toxic effects, pharmacokinetics and pharmacodynamics. This may identify suitable antiviral and anticancer drugs in the near future. Considering all these activities, the present review is focused on the chemical aspects of DG with a detailed account on the mechanisms of action of DG. An attempt is also made to comment on the status of clinical trials of DG along with the possible limitations in studies based on available literature through September 2020.

Newly Identified COVID-19 Drug Candidates Based on Computational Strategies

The COVID-19 has raised a public health catastrophe in early 2020 worldwide. Despite several approved vaccines that have repressed the pandemic and decreased the mortality rate since then, attempts to discover an effective antiviral drug have not indicated reliable results. In this research, in silico studies (virtual screening and molecular docking) were performed based on quinoline structure to identify novel drug candidates against SARS-CoV-2 before laboratory evaluations. A chemical library consisting of 548 compounds was collected from literature mining of five databases to select the best ligands interacting with three target proteins of SARS-CoV-2, including the main protease, spike protein, and chimeric receptor-binding domain in a complex of human angiotensin-converting enzyme 2. The top five compounds that presented suitable binding energy against each target protein are reported in detail for the first time. Notably, new compound N-4-(6-methyl-3-pyridinyl) phenyl)-9-acridinamine showed high affinity to all selected proteins. These identified compounds will help in speeding up the drug development against COVID-19.

Anthranilamides with quinoline and β-carboline scaffolds: design, synthesis, and biological activity

In the present study, we report the design and synthesis of novel amide-type hybrid molecules based on anthranilic acid and quinoline or β-carboline heterocyclic scaffolds. Three types of biological screenings were performed: (i) in vitro antiproliferative screening against a panel of solid tumor and leukemia cell lines, (ii) antiviral screening against several RNA viruses, and (iii) anti-quorum sensing screening using gram-negative Chromobacterium violaceum as the reporter strain. Antiproliferative screening revealed a high activity of several compounds. Anthranilamides 12 and 13 with chloroquine core and halogenated anthranilic acid were the most active agents toward diverse cancer cell lines such as glioblastoma, pancreatic adenocarcinoma, colorectal carcinoma, lung carcinoma, acute lymphoblastic, acute myeloid, chronic myeloid leukemia, and non-Hodgkin lymphoma, but also against noncancerous cell lines. Boc-protected analogs 2 and 3 showed moderate activities against the tested cancer cells without toxic effects against noncancerous cells. A nonhalogenated quinoline derivative 10 with N-benzylanthranilic acid residue was equally active as 12 and 13 and selective toward tumor cells. Chloroquine and quinoline anthranilamides 10-13 exerted pronounced antiviral effect against human coronaviruses 229E and OC43, whereas 12 and 13 against coronavirus OC43 (EC₅₀ values in low micromolar range; selectivity indices from 4.6 to > 10.4). Anthranilamides 14 and 16 with PQ core inhibited HIV-1 with EC₅₀ values of 9.3 and 14.1 µM, respectively. Compound 13 displayed significant anti-quorum/biofilm effect against the quorum sensing reporter strain (IC₅₀ of 3.7 μM) with no apparent bactericidal effect.

Natural products as a therapy to combat against SARS-CoV-2 virus infection

The novel coronavirus infection (COVID-19) first reported in December 2019, has become serious global life-threatening disease that has created huge health care crises. Despite huge number of clinical trials for drug and vaccine, only few successful candidates are in market, which led to problem of demand and supply. The low- and middle-income countries faces major health crisis due to financial issues. Studies to search plant originated natural bioactive molecules for prophylactic and therapeutic of COVID-19 infection has gained considerable attention, due to their low-cost, easy availability and lesser side effects. Natural products and herbal medicine have long been known for their role in treating respiratory infections and many of them have been approved/under trial as drugs or over-the-counter food additives to lessen the symptoms. It is undisputable fact that herbal/natural molecules’ medicine is still a promising resource and used as precursor for drug discovery to search prospective prophylactic candidate against COVID-19. These bioactive compounds bind with potential therapeutic target of SARS-COV-2 such as ACE II, Spike protein, TMPRESS, RdRp, Main proteases and endoribonuclease and may prevent or at least slow down the SARS-CoV-2 infection. Therefore, several numbers of clinical trials have registered to investigate the potentials of natural product to halt disease progression. The main aim of present chapter is to discuss the potential role of natural molecules which can be used as therapeutic drugs for treatment of COVID-19 and thus helpful to curb down the mortality rate.

Computer-aided discovery, design, and investigation of COVID-19 therapeutics

Coronavirus disease 2019 (COVID-19) pandemic is currently the most serious public health threat faced by mankind. Thus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, is being intensively investigated. Several vaccines are now available for clinical use. However, owing to the highly mutated nature of RNA viruses, the SARS-CoV-2 is changing at a rapid speed. Breakthrough infections by SARS-CoV-2 variants have been seen in vaccinated individuals. As a result, effective therapeutics for treating COVID-19 patients is urgently required. With the advance of computer technology, computational methods have become increasingly powerful in the biomedical research and pharmaceutical drug discovery. The applications of these techniques have largely reduced the costs and simplified processes of pharmaceutical drug developments. Intensive and extensive studies on SARS-CoV-2 proteins have been carried out and three-dimensional structures of the major SARS-CoV-2 proteins have been resolved and deposited in the Protein Data Bank. These structures provide the foundations for drug discovery and design using the structure-based computations, such as molecular docking and molecular dynamics simulations. In this review, introduction to the applications of computational methods in the discovery and design of novel drugs and repurposing of existing drugs for the treatments of COVID-19 is given. The examples of computer-aided investigations and screening of COVID-19 effective therapeutic compounds, functional peptides, as well as effective molecules from the herb medicines are discussed.

Novel treatments and trials in COVID-19

Coronavirus disease 2019 (COVID-19), the disease arising from the beta coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has presented a major challenge to health-care systems and societies across the world. Although previous highly pathogenic coronaviruses have emerged, namely severe acute respiratory syndrome coronavirus 1 and Middle East respiratory syndrome coronavirus, neither had the spread nor the persistence to result in large clinical trials of drug therapy. Much of our therapeutic knowledge in these viruses was therefore informed by inference from observational, in vitro, and experimental model studies. As a result, when SARS-CoV-2 emerged with a noted high morbidity and mortality, initial therapeutic drug treatment was often empiric. There are currently over 4400 trials concerning COVID-19 registered on the World Health Organization international clinical trials registry, and while not all these are interventional therapeutic trials, this illustrates the desire of the international clinical-scientific community to develop systematic and evidence-based approaches for the management of this major threat. This chapter discusses the broad strategies of therapeutic pharmacological approaches suggested, namely antiviral therapy, antiinflammatories, and immunomodulatory. Nonpharmacological approaches are also to be discussed. Then, it reviews the approaches to trials and trial design, the development and use of core outcome sets, and regulation of trials in pandemic settings. It reviews the publication and preprint availability of completed trials before discussing the ethics of empiric treatment outside the context of trials.

Clinical efficacy and safety of Qingshu Yiqi decoction as a complementary and alternative therapy for COVID-19 with Delta variant: A protocol for systematic review and meta-analysis

BACKGROUND

Qingshu Yiqi decoction combined with general western medicine are important and prevalent recently treatment method of corona virus disease 2019 (COVID-19) with Delta variant, but the efficacy and safety were not clear. This meta-analysis aims to clarify their clinical efficacy and safety thus to provide evidence for clinical application.

METHODS

We searched Chinese databases CNKI, Wanfang, VIP and English databases PubMed, Cochrane Library, Embase for the current study. The retrieval time was from the establishment to November, 2021. Literature quality was evaluated according to the bias risk assessment criteria of Cochrane Collaboration network. RevMan 5.3 and Stata 12.0 were used to perform this research.

RESULTS

The efficacy and safety of Qingshu Yiqi decoction combined with western medicine for COVID-19 with Delta variant were evaluated in terms of total effective rate, TCM syndrome score, negative conversation rate of viral nucleic acid, disappearance rate of clinical symptoms (such as fever, cough, and fatigue), CT improvement, white blood cell (WBC), lymphocyte (LYM) and adverse reaction rate.

CONCLUSION

This study provides reliable evidence-based support for the clinical efficacy and safety of Qingshu Yiqi decoction as a complementary and alternative therapy for COVID-19 with Delta variant.

PROSPERO REGISTRATION NUMBER

CRD42021271606.

Scoping insight on antiviral drugs against COVID-19

Background

COVID-19 is an ongoing viral pandemic produced by SARS-CoV-2. In light of in vitro efficacy, several medications were repurposed for its management. During clinical use, many of these medications produced inconsistent results or had varying limitations.

Objective

The purpose of this literature review is to explain the variable efficacy or limitations of Lopinavir/Ritonavir, Remdesivir, Hydroxychloroquine, and Favipiravir in clinical settings.

Method

A study of the literature on the pharmacodynamics (PD), pharmacokinetics (PK), safety profile, and clinical trials through academic databases using relevant search terms.

Results & discussion

The efficacy of an antiviral drug against COVID-19 is associated with its ability to achieve therapeutic concentration in the lung and intestinal tissues. This efficacy depends on the PK properties, particularly protein binding, volume of distribution, and half-life. The PK and PD of the model drugs need to be integrated to predict their limitations.

Conclusion

Current antiviral drugs have varying pharmacological constraints that may associate with limited efficacy, especially in severe COVID-19 patients, or safety concerns.

Chitosan Nanoparticles for Antiviral Drug Delivery: A Novel Route for COVID-19 Treatment

Chitosan has been investigated in several biological fields, including drug and gene delivery, tissue engineering antiviral and immunological adjuvant methods. It's a cationic copolymer of N-acetyl glucosamine and D-glucosamine with different molecular chain lengths, compositions, and sequences than N-acetyl glucosamine and D-glucosamine. It is biocompatible and cyto-compatible, as well as recyclable and bioresorbable. As effective drug delivery methods, chitosan nanoparticles are shaped into several pathways. The purpose of this article is to provide an overview of its antiviral application as a nanocarrier for antiviral medications, highlighting the benefits, limitations, and downsides. In this review, we will report the most recent COVID-19 vaccination advances. It will also be discussed what the future holds for chitosan nanoparticles in the treatment of coronaviruses.

SARS-COV-2, infection, transmission, transcription, translation, proteins, and treatment: A review

In this review, we describe the key molecular entities involved in the process of infection by SARS-CoV-2, while also detailing how those key entities influence the spread of the disease. We further introduce the molecular mechanisms of preventive and treatment strategies including drugs, antibodies, and vaccines.