Repurposing of well-known medications as antivirals: hydroxychloroquine and chloroquine - from HIV-1 infection to COVID-19

The effects of hydroxychloroquine and its promising use in refractory obstetric antiphospholipid syndrome

Hydroxychloroquine (HCQ) is obtained by hydroxylation of chloroquine (CQ) and the first indication was malaria. Nowadays, HCQ is commonly used in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) with favorable results. Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombosis and/or pregnancy morbidity and persistent positivity of antiphospholipid antibodies. Around 20-30% of pregnant women with APS develop adverse pregnancy outcomes despite conventional treatment with aspirin and heparin, called refractory obstetric APS. Interestingly, HCQ has shown positive effects on top of the standard of care in some refractory obstetric APS patients. HCQ mechanisms of action in APS comprise its ability to bind sialic acid present in cell membranes, its capacity to block the binding of antiphospholipid antibodies to the cell and the induced increase of pH in extracellular and intracellular compartments. However, the precise mechanisms of HCQ in the specific situation of refractory APS still need to be fully clarified. Therefore, this review summarizes the known modulating effects of HCQ and CQ, their side effects and use in APS and different pathologies to understand the benefit effects and the mechanism of action of HCQ in refractory obstetric APS.

Efficacy and Safety of Remdesivir in Hospitalized Pediatric COVID-19: A Retrospective Case-Controlled Study

Introduction

While most children experience mild coronavirus disease 2019 (COVID-19) infections, a minority of cases progress to severe or critical illness. This study aimed to assess the efficacy and safety of Remdesivir (RDV) therapy in children with moderate to severe COVID-19, enhancing clinical decision-making and expanding our understanding of antiviral treatments for pediatric patients.

Methods

The study included 60 patients, 38 receiving RDV treatment and 22 serving as the control group. Data was collected retrospectively from January 2021 to January 2022 through electronic hospital records.

Results

Regarding the main clinical symptoms reported, most patients experienced Upper Respiratory Tract Infections (93.3%), indicating respiratory involvement. Additional symptoms included Central Nervous System (11.7%) and Gastrointestinal (10.0%). Among the 38 cases in the RDV group included in the study, the adverse effects associated with using RDV: Hypoalbuminemia in 19 cases (50.0%) and anemia in 18 cases (47.4%), making them the most common adverse effects. Only one case in the RDV group experienced non-RDV-related death with a different clinical diagnosis. The results showed that RDV treatment was well-tolerated in pediatric patients, with no significant differences in hospital stay and oxygen treatment compared to the control group with P values (0.2, 0.18), respectively.

Conclusion

The outcomes indicate that Remdesivir may represent a safe and therapeutic choice for children with coronavirus disease 2019 (COVID-19).

Small molecules targeting endocytic uptake and recycling pathways

Over the past years a growing number of studies highlighted the pivotal role of intracellular trafficking in cell physiology. Among the distinct transport itineraries connecting the endocytic system, both internalization (endocytosis) and recycling (endocytic recycling) pathways were found fundamental to ensure cellular sensing, cell-to-cell communication, cellular division, and collective cell migration in tissue specific-contexts. Consistently, the dysregulation of endocytic trafficking pathways is correlated with several human diseases including both cancers and neurodegeneration. Aimed at suppress specific intracellular trafficking routes involved in disease onset and progression, huge efforts have been made to identify small molecule inhibitors with suitable pharmacological properties for in vivo administration. Here, we review most used drugs and recently discovered small molecules able to block endocytosis and endocytic recycling pathways. We characterize such pharmacological inhibitors by emphasizing their target specificity, molecular affinity, biological activity and efficacy in both in vitro and in vivo experimental models.

Sub-cellular sequestration of alkaline drugs in lysosomes: new insights for pharmaceutical development of lysosomal fluid

Background and purpose

Lysosomal-targeted drug delivery can open a new strategy for drug therapy. However, there is currently no universally accepted simulated or artificial lysosomal fluid utilized in the pharmaceutical industry or recognized by the United States Pharmacopeia (USP).

Experimental procedure

We prepared a simulated lysosomal fluid (SLYF) and compared its composition to a commercial artificial counterpart. The developed fluid was used to test the dissolution of a commercial product (Robitussin^®) of a lysosomotropic drug (dextromethorphan) and to investigate in-vitro lysosomal trapping of two model drugs (dextromethorphan and (+/-) chloroquine).

Findings/Results

The laboratory-prepared fluid or SLYF contained the essential components for the lysosomal function in concentrations reflective of the physiological values, unlike the commercial product. Robitussin^® passed the acceptance criteria for the dissolution of dextromethorphan in 0.1 N HCl medium (97.7% in less than 45 min) but not in the SLYF or the phosphate buffer media (72.6% and 32.2% within 45 min, respectively). Racemic chloroquine showed higher lysosomal trapping (51.9%) in the in-vitro model than dextromethorphan (28.3%) in a behavior supporting in-vivo findings and based on the molecular descriptors and the lysosomal sequestration potential of both.

Conclusion and implication

A standardized lysosomal fluid was reported and developed for in-vitro investigations of lysosomotropic drugs and formulations.

Hydroxychloroquine Alleviates EAU by Inhibiting Uveitogenic T Cells and Ameliorating Retinal Vascular Endothelial Cells Dysfunction

Purpose

Inflammation triggers the activation of CD4⁺T cells and the breakdown of blood–retinal barrier, thus contributing to the pathology of experimental autoimmune uveitis (EAU). We explored the anti-inflammatory effect of hydroxychloroquine (HCQ) on EAU and the potential mechanisms active in T cells and retinal vascular endothelial cells (RVECs).

Methods

C57BL/6J mice were immunized with interphotoreceptor retinoid binding protein 1-20 (IRBP_1–20) to induce EAU and then treated with the vehicle or HCQ (100 mg/kg/day). On day 7, 14, 21, 30 and 60 after immunization, clinical scores were evaluated. On day 14, histopathological scores were assessed, and retinas, spleens, and lymph nodes were collected for quantitative polymerase chain reaction or flow cytometry analysis. RVEC dysfunction was induced by tumor necrosis factor α (TNF-α) stimulation. The expression of cytokines, chemokines, adhesion molecules, and lectin-like oxidized LDL receptor-1 (LOX-1)/nuclear factor κB (NF-κB) was measured in RVECs with or without HCQ.

Results

HCQ treatment protected mice from uveitis, evidenced by reduced expression of inflammatory factors, chemokines, and adhesion molecules in the retina. In systemic immune response, HCQ inhibited the activation of naïve CD4⁺T cells and frequencies of T effector cells, and promoted T regulatory cells. HCQ decreased IRBP_1-20–specific T cell responses and proliferation of CD4⁺T cells in vitro. Further studies established that TNF-α induced RVECs to express inflammatory cytokines, chemokines, and adhesion molecules, whereas HCQ alleviated the alterations via the LOX-1/NF-κB pathways.

Conclusions

HCQ alleviates EAU by regulating the Teff/Treg balance and ameliorating RVECs dysfunction via the LOX-1/NF-κB axis. HCQ may be a promising therapeutic candidate for uveitis.

Can anti-parasitic drugs help control COVID-19?

Novel COVID-19 is a public health emergency that poses a serious threat to people worldwide. Given the virus spreading so quickly, novel antiviral medications are desperately needed. Repurposing existing drugs is the first strategy. Anti-parasitic drugs were among the first to be considered as a potential treatment option for this disease. Even though many papers have discussed the efficacy of various anti-parasitic drugs in treating COVID-19 separately, so far, no single study comprehensively discussed these drugs. This study reviews some anti-parasitic recommended drugs to treat COVID-19, in terms of function and in vitro as well as clinical results. Finally, we briefly review the advanced techniques, such as artificial intelligence, that have been used to find effective drugs for the treatment of COVID-19.

Multipurpose Drugs Active Against Both Plasmodium spp. and Microorganisms: Potential Application for New Drug Development

Malaria, a disease caused by the protozoan parasites Plasmodium spp., is still causing serious problems in endemic regions in the world. Although the WHO recommends artemisinin combination therapies for the treatment of malaria patients, the emergence of artemisinin-resistant parasites has become a serious issue and underscores the need for the development of new antimalarial drugs. On the other hand, new and re-emergences of infectious diseases, such as the influenza pandemic, Ebola virus disease, and COVID-19, are urging the world to develop effective chemotherapeutic agents against the causative viruses, which are not achieved to the desired level yet. In this review article, we describe existing drugs which are active against both Plasmodium spp. and microorganisms including viruses, bacteria, and fungi. We also focus on the current knowledge about the mechanism of actions of these drugs. Our major aims of this article are to describe examples of drugs that kill both Plasmodium parasites and other microbes and to provide valuable information to help find new ideas for developing novel drugs, rather than merely augmenting already existing drug repurposing efforts.

Mechanism of Blood-Heart-Barrier Leakage: Implications for COVID-19 Induced Cardiovascular Injury

Although blood–heart-barrier (BHB) leakage is the hallmark of congestive (cardio-pulmonary) heart failure (CHF), the primary cause of death in elderly, and during viral myocarditis resulting from the novel coronavirus variants such as the severe acute respiratory syndrome novel corona virus 2 (SARS-CoV-2) known as COVID-19, the mechanism is unclear. The goal of this project is to determine the mechanism of the BHB in CHF. Endocardial endothelium (EE) is the BHB against leakage of blood from endocardium to the interstitium; however, this BHB is broken during CHF. Previous studies from our laboratory, and others have shown a robust activation of matrix metalloproteinase-9 (MMP-9) during CHF. MMP-9 degrades the connexins leading to EE dysfunction. We demonstrated juxtacrine coupling of EE with myocyte and mitochondria (Mito) but how it works still remains at large. To test whether activation of MMP-9 causes EE barrier dysfunction, we hypothesized that if that were the case then treatment with hydroxychloroquine (HCQ) could, in fact, inhibit MMP-9, and thus preserve the EE barrier/juxtacrine signaling, and synchronous endothelial-myocyte coupling. To determine this, CHF was created by aorta-vena cava fistula (AVF) employing the mouse as a model system. The sham, and AVF mice were treated with HCQ. Cardiac hypertrophy, tissue remodeling-induced mitochondrial-myocyte, and endothelial-myocyte contractions were measured. Microvascular leakage was measured using FITC-albumin conjugate. The cardiac function was measured by echocardiography (Echo). Results suggest that MMP-9 activation, endocardial endothelial leakage, endothelial-myocyte (E-M) uncoupling, dyssynchronous mitochondrial fusion-fission (Mfn2/Drp1 ratio), and mito-myocyte uncoupling in the AVF heart failure were found to be rampant; however, treatment with HCQ successfully mitigated some of the deleterious cardiac alterations during CHF. The findings have direct relevance to the gamut of cardiac manifestations, and the resultant phenotypes arising from the ongoing complications of COVID-19 in human subjects.

Remdesivir and EIDD-1931 Interact with Human Equilibrative Nucleoside Transporters 1 and 2: Implications for Reaching SARS-CoV-2 Viral Sanctuary Sites

Equilibrative nucleoside transporters (ENTs) are present at the blood-testis barrier (BTB), where they can facilitate antiviral drug disposition to eliminate a sanctuary site for viruses detectable in semen. The purpose of this study was to investigate ENT-drug interactions with three nucleoside analogs, remdesivir, molnupiravir, and molnupiravir's active metabolite, β-d-N4-hydroxycytidine (EIDD-1931), and four non-nucleoside molecules repurposed as antivirals for coronavirus disease 2019 (COVID-19). The study used three-dimensional pharmacophores for ENT1 and ENT2 substrates and inhibitors and Bayesian machine learning models to identify potential interactions with these transporters. In vitro transport experiments demonstrated that remdesivir was the most potent inhibitor of ENT-mediated [3H]uridine uptake (ENT1 IC50: 39 μM; ENT2 IC50: 77 μM), followed by EIDD-1931 (ENT1 IC50: 259 μM; ENT2 IC50: 467 μM), whereas molnupiravir was a modest inhibitor (ENT1 IC50: 701 μM; ENT2 IC50: 851 μM). Other proposed antivirals failed to inhibit ENT-mediated [3H]uridine uptake below 1 mM. Remdesivir accumulation decreased in the presence of 6-S-[(4-nitrophenyl)methyl]-6-thioinosine (NBMPR) by 30% in ENT1 cells (P = 0.0248) and 27% in ENT2 cells (P = 0.0054). EIDD-1931 accumulation decreased in the presence of NBMPR by 77% in ENT1 cells (P = 0.0463) and by 64% in ENT2 cells (P = 0.0132), which supported computational predictions that both are ENT substrates that may be important for efficacy against COVID-19. NBMPR failed to decrease molnupiravir uptake, suggesting that ENT interaction is likely inhibitory. Our combined computational and in vitro data can be used to identify additional ENT-drug interactions to improve our understanding of drugs that can circumvent the BTB. SIGNIFICANCE STATEMENT: This study identified remdesivir and EIDD-1931 as substrates of equilibrative nucleoside transporters 1 and 2. This provides a potential mechanism for uptake of these drugs into cells and may be important for antiviral potential in the testes and other tissues expressing these transporters.

How to exploit different endocytosis pathways to allow selective delivery of anticancer drugs to cancer cells over healthy cells

It was recently shown that it is possible to exploit the nanoparticle shape to selectively target endocytosis pathways found in cancer and not healthy cells. It is important to understand and compare the endocytosis pathways of nanoparticles in both cancer and healthy cells to restrict the healthy cells from taking up anticancer drugs to help reduce the side effects for patients. Here, the clathrin-mediated endocytosis inhibitor, hydroxychloroquine, and the anticancer drug, doxorubicin, are loaded into the same mesoporous silica nanorods. The use of nanorods was found to restrict the uptake by healthy cells but allowed cancer cells to take up the nanorods via the macropinocytosis pathway. Furthermore, it is shown that the nanorods can selectively deliver doxorubicin to the nucleus of breast cancer cells and to the cytoplasm of pancreatic cancer cells. The dual-drug-loaded nanorods were able to selectively kill the breast cancer cells in the presence of healthy breast cells. This study opens exciting possibilities of targeting cancer cells based on the material shape rather than targeting antibodies.

It was recently shown that it is possible to exploit the nanoparticle shape to selectively target endocytosis pathways found in cancer and not healthy cells.

Attenuation of chloroquine and hydroxychloroquine on the invasive potential of bladder cancer through targeting matrix metalloproteinase 2 expression

Bladder cancer (BC), one of the most common urological neoplastic disorders in men, has an extremely low survival rate because of its tendency to metastasize. The anticancer drugs chloroquine (CQ) and hydroxy CQ (HCQ) might inhibit tumor progression and invasiveness. However, the mechanism by which CQ and HCQ influence BC is undetermined. In this study, CQ and HCQ treatments inhibited the migration and invasion of two BC cell types (5637 and T24) through expression modulation of matrix metalloproteinase-2 (MMP-2), which belongs to the matrix MMP family and is a key mediator of cancer progression. Moreover, additional data revealed that the migrative and invasive effects of BC cells treated with CQ or HCQ were abolished after treatment with rapamycin, which induces autophagy, demonstrating that CQ and HCQ functions in BC are based on autophagy inhibition. In conclusion, our research demonstrated that CQ and HCQ regulated cell motility in BC through MMP-2 downregulation by targeting autophagy functions, providing a novel therapeutic strategy for BC treatment.

COVID-19: potential therapeutics for pediatric patients

The global spread of COVID-19 has imparted significant economic, medical, and social burdens. Like adults, children are affected by this pandemic. However, milder clinical symptoms are often experienced by them. Only a minimal proportion of the affected patients may develop severe and complicated COVID-19. Supportive treatment is recommended in all patients. Antiviral and immunomodulatory medications are spared for hospitalized children with respiratory distress or severe to critical disease. Up till now, remdesivir is the only USFDA-approved anti-COVID-19 medication indicated in the majority of symptomatic patients with moderate to severe disease. Dexamethasone is solely recommended in patients with respiratory distress maintained on oxygen or ventilatory support. The use of these medications in pediatric patients is founded on evidence deriving from adult studies. No randomized controlled trials (RCTs) involving pediatric COVID-19 patients have assessed these medications' efficacy and safety, among others. Similarly, three novel monoclonal anti-SARS-CoV-2 spike protein antibodies, bamlanivimab, casirivimab and imdevimab, have been recently authorized by the USFDA. Nonetheless, their efficacy has not been demonstrated by multiple RCTs. In this review, we aim to dissect the various potential therapeutics used in children with COVID-19. We aspire to provide a comprehensive review of the available evidence and display the mechanisms of action and the pharmacokinetic properties of the studied therapeutics. Our review offers an efficient and practical guide for treating children with COVID-19.

The lysosome as a master regulator of iron metabolism

Intracellular iron fulfills crucial cellular processes, including DNA synthesis and mitochondrial metabolism, but also mediates ferroptosis, a regulated form of cell death driven by lipid-based reactive oxygen species (ROS). Beyond their established role in degradation and recycling, lysosomes occupy a central position in iron homeostasis and integrate metabolic and cell death signals emanating from different subcellular sites. We discuss the central role of the lysosome in preserving iron homeostasis and provide an integrated outlook of the regulatory circuits coupling the lysosomal system to the control of iron trafficking, interorganellar crosstalk, and ferroptosis induction. We also discuss novel studies unraveling how deregulated lysosomal iron-handling functions contribute to cancer, neurodegeneration, and viral infection, and can be harnessed for therapeutic interventions.

Human lung-on-chips: Advanced systems for respiratory virus models and assessment of immune response

Respiratory viral infections are leading causes of death worldwide. A number of human respiratory viruses circulate in all age groups and adapt to person-to-person transmission. It is vital to understand how these viruses infect the host and how the host responds to prevent infection and onset of disease. Although animal models have been widely used to study disease states, incisive arguments related to poor prediction of patient responses have led to the development of microfluidic organ-on-chip models, which aim to recapitulate organ-level physiology. Over the past decade, human lung chips have been shown to mimic many aspects of the lung function and its complex microenvironment. In this review, we address immunological responses to viral infections and elaborate on human lung airway and alveolus chips reported to model respiratory viral infections and therapeutic interventions. Advances in the field will expedite the development of therapeutics and vaccines for human welfare.

Virtual screening of phytochemical compounds as potential inhibitors against SARS-CoV-2 infection

Background

The present pandemic situation due to coronavirus has led to the search for newer prevention, diagnostic, and treatment methods. The onset of the corona infection in a human results in acute respiratory illness followed by death if not diagnosed and treated with suitable antiretroviral drugs. With the unavailability of the targeted drug treatment, several repurposed drugs are being used for treatment. However, the side-effects of the drugs urges us to move to a search for newer synthetic- or phytochemical-based drugs. The present study investigates the use of various phytochemicals virtually screened from various plant sources in Western Ghats, India, and subsequently molecular docking studies were performed to identify the efficacy of the drug in retroviral infection particularly coronavirus infection.

Results

Out of 57 phytochemicals screened initially based on the structural and physicochemical properties, 39 were effectively used for the docking analysis. Finally, 5 lead compounds with highest hydrophobic interaction and number of H-bonds were screened. Results from the interaction analysis suggest Piperolactam A to be pocketed well with good hydrophobic interaction with the residues in the binding region R1. ADME and toxicity profiling also reveals Piperolactam A with higher LogS values indicating higher permeation and hydrophilicity. Toxicity profiling suggests that the 5 screened compounds to be relatively safe.

Conclusion

The in silico methods used in this study suggests that the compound Piperolactam A to be the most effective inhibitor of S-protein from binding to the GRP78 receptor. By blocking the binding of the S-protein to the CS-GRP78 cell surface receptor, they can inhibit the binding of the virus to the host.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43088-021-00095-x.

Hydroxychloroquine in the COVID-19 pandemic era: in pursuit of a rational use for prophylaxis of SARS-CoV-2 infection

INTRODUCTION

Over the last few months, coronavirus disease 2019 (COVID-19) pandemic caused by the novel coronavirus SARS-CoV-2 has posed a serious threat to public health on a global scale. Given the current lack of an effective vaccine, several drugs have been repurposed for treatment and prophylaxis of COVID-19 in an attempt to find an effective cure.

AREAS COVERED

The antimalarial drug hydroxychloroquine (HCQ) initially garnered widespread attention following the publication of preliminary results showing that this drug exerts an anti-SARS-CoV-2 activity in vitro.

EXPERT OPINION

To date, clinical evidence suggests lack of benefit from HCQ use for the treatment of hospitalized patients with COVID-19. In such patients, HCQ also appears to be associated with an increased risk of QT interval prolongation and potentially lethal ventricular arrhythmias. Therefore, FDA has recently revoked the Emergency Use Authorization (EUA) for emergency use of HCQ and chloroquine to treat COVID-19. Conversely, whether HCQ use may represent an effective prophylactic strategy against COVID-19 is a separate question that still remains to be answered. In addition, relevant aspects regarding the potential risks and benefits of HCQ need to be clarified, in pursuit of a rational use of this drug in the COVID-19 pandemic era.

Autophagy Modulation in Lymphocytes From COVID-19 Patients: New Therapeutic Target in SARS-COV-2 Infection

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the novel coronavirus, causing coronavirus disease 2019 (COVID-19). During virus infection, several pro-inflammatory cytokines are produced, leading to the "cytokine storm." Among these, interleukin (IL)-6, tumor necrosis factor-α (TNF-α), and IL-1β seem to have a central role in the progression and exacerbation of the disease, leading to the recruitment of immune cells to infection sites. Autophagy is an evolutionarily conserved lysosomal degradation pathway involved in different aspects of lymphocytes functionality. The involvement of IL-6, TNF-α, and IL-1β in autophagy modulation has recently been demonstrated. Moreover, preliminary studies showed that SARS-CoV-2 could infect lymphocytes, playing a role in the modulation of autophagy. Several anti-rheumatic drugs, now proposed for the treatment of COVID-19, could modulate autophagy in lymphocytes, highlighting the therapeutic potential of targeting autophagy in SARS-CoV-2 infection.

Combining hydroxychloroquine and minocycline: potential role in moderate to severe COVID-19 infection

INTRODUCTION

Patients with moderate to severe COVID-19 infection require specific drugs to prevent the morbidity and mortality. Hydroxychloroquine (HCQ) has shown some promise in the management of COVID 19. Minocycline, because of its anticytokine and other useful properties can be an ideal candidate for combining with HCQ.

AREAS COVERED

Here we review the need and mechanisms and reasons for combining HCQ and minocycline moderate to severe COVID-19 infection. We also reviewed the advantages, potential safety concerns and precautions to be taken, while combining HCQ and minocycline.

EXPERT OPINION

Combining HCQ and minocycline offers many advantages in the management of moderate to severe COVID-19 infection. Both drugs are cheaper, widely available and long-term safety data and contraindications are well known. We do not recommend this combination for prophylaxis or use in asymptomatic or mild disease patients as this can lead to unnecessary safety concerns. Additive antimicrobial and anticytokine effects of both drugs may reduce the morbidity and mortality among patients with COVID-19 and may act as a cheaper alternative to the costlier drugs, however, thorough clinical research is warranted. We call upon public and private healthcare bodies to come up with large well-designed clinical studies for generating evidence-based recommendations.