Chloroquine: modes of action of an undervalued drug

Advancements on the impact of hydroxychloroquine in systemic lupus erythematosus

Hydroxychloroquine (HCQ) has gained significant attention as a therapeutic option for systemic lupus erythematosus (SLE) because of its multifaceted mechanism of action. It is a lipophilic, lysosomotropic drug, that easily traverses cell membranes and accumulates in lysosomes. Once accumulated, HCQ alkalizes lysosomes within the cytoplasm, thereby disrupting their function and interfering with processes like antigen presentation. Additionally, HCQ has shown potential in modulating T-cell responses, inhibiting cytokine production, and influencing Toll-like receptor signaling. Its immunomodulatory effects have generated interest in its application for autoimmune disorders. Despite its established efficacy, uncertainties persist regarding the optimal therapeutic concentrations and their correlation with adverse effects such as retinal toxicity. Therefore, standardized dosing and monitoring guidelines are crucial. In this study, we provide a comprehensive review of the mechanisms, efficacy, dosing variations, and retinal toxicity profiles of HCQ, which are essential to optimize SLE treatment protocols and ensure patient safety.

In vivo antimalarial effect of 1-hydroxy-5,6,7-trimethoxyxanthone isolated from Mammea siamensis T. Anders. flowers: pharmacokinetic and acute toxicity studies

BACKGROUND

The potent antiplasmodial activity of 1-hydroxy-5,6,7-trimethoxyxanthone (HTX), isolated from Mammea siamensis T. Anders. flowers, has previously been demonstrated in vitro. However, its in vivo activity has not been reported. Therefore, this study aimed to investigate the antimalarial activity and acute toxicity of HTX in a mouse model and to evaluate the pharmacokinetic profile of HTX following a single intraperitoneal administration.

METHODS

The in vivo antimalarial activity of HTX was evaluated using a 4-day suppressive test. Mice were intraperitoneally injected with Plasmodium berghei ANKA strain and given HTX daily for 4 days. To detect acute toxicity, mice received a single dose of HTX and were observed for 14 days. Additionally, the biochemical parameters of the liver and kidney functions as well as the histopathology of liver and kidney tissues were examined. HTX pharmacokinetics after intraperitoneal administration was also investigated in a mouse model. Liquid chromatography triple quadrupole mass spectrometry was used to quantify plasma HTX and calculate pharmacokinetic parameters with the PKSolver software.

RESULTS

HTX at 10 mg/kg body weight significantly suppressed parasitemia in malaria-infected mice by 74.26%. Mice treated with 3 mg/kg HTX showed 46.88% suppression, whereas mice treated with 1 mg/kg displayed 34.56% suppression. Additionally, no symptoms of acute toxicity were observed in the HTX-treated groups. There were no significant alterations in the biochemical parameters of the liver and kidney functions and no histological changes in liver or kidney tissues. Following intraperitoneal HTX administration, the pharmacokinetic profile exhibited a maximum concentration (Cmax) of 94.02 ng/mL, time to attain Cmax (Tmax) of 0.5 h, mean resident time of 14.80 h, and elimination half-life of 13.88 h.

CONCLUSIONS

HTX has in vivo antimalarial properties against P. berghei infection. Acute toxicity studies of HTX did not show behavioral changes or mortality. The median lethal dose was greater than 50 mg/kg body weight. Pharmacokinetic studies showed that HTX has a long elimination half-life; hence, shortening the duration of malaria treatment may be required to minimize toxicity.

Preliminary insight into the potential antiplasmodial activity and cytotoxicity of Bufo bufo and Incilius alvarius poison

The rise and spread of resistant Plasmodium falciparum strains are responsible for an increase in therapeutic failures in many of the regions endemic with malaria. The need for new therapeutic candidates is now more urgent than ever. Animal venoms have long been considered as interesting resources to exploit in terms of potential therapeutic candidates. Among these, the cutaneous secretions of toads constitute a rich and diverse source of bioactive molecules. We focused on two different species: Bufo bufo and Incilius alvarius. The dried secretions underwent a solvent-based extraction and were submitted to a systematic bio-guided fractionation approach using preparative thin-layer chromatography. Initial crude extracts were tested in vitro for their antiplasmodial activity. Based on these results, only crude extracts displaying IC₅₀ < 100 μg/mL were considered for further fractionation. All extracts and fractions, including those that did not display antiplasmodial properties, were characterized by chromatographic (LC-UV/MS) and spectrometric techniques (HRMS). Antiplasmodial activity was evaluated in vitro using a chloroquine-sensitive strain (3D7) and a resistant one (W2). Toxicity was assessed on normal human cells for the samples displaying IC₅₀ < 100 μg/mL. Crude extracts from Bufo bufo secretions exhibited no appreciable antiplasmodial activities. However, the methanol and dichloromethane extracts from Incilius alvarius secretions gave IC₅₀ of (34 ± 4) μg/mL and (50 ± 1) μg/mL respectively when tested on W2 strain. No significant effect was observed on 3D7. This poison would warrant further investigation in terms of its antiplasmodial potential. Following preliminary characterization, it was revealed that the fractions of interest contained mainly bufotoxins, bufagins and alkaloids.

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.

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.

The Effect of A2E on the Ca2+-PKC Signaling Pathway in Human RPE Cells Exposed to Blue Light

Aims

In a model of blue light-induced damage in N-retinylidene-N-retinylethanolamine (A2E)-loaded human retinal pigment epithelial (RPE) cells, we examined the effect of A2E on the calcium (Ca²⁺)-protein kinase C (PKC) signaling pathway.

Methods

Primary human RPE cells were cultured, and the cells in the 4th–6th passages were used in this study. The cells were divided into 5 groups: control cells (no A2E, no blue light), blue light-treated cells, blue light + chloroquine-treated cells, blue light + A2E-treated cells, and blue light + A2E + chloroquine-treated cells. The cells were first treated with chloroquine (15 μM for 12 h) and then loaded with A2E (25 μM for 2 h).The blue light intensity was 2000 ± 500 lux, and the duration was 6 h. After blue light exposure, the cells were cultured for 24 h. Fluo-3/AM staining was used to determine the level of cytoplasmic Ca²⁺, and the cells were photographed using a laser scanning confocal microscope to analyze the fluorescence intensity. The intracellular levels of inositol triphosphate (IP3) and diacylglycerol (DAG) were measured by enzyme-linked immunosorbent assay (ELISA). Intracellular PKC activity was measured with a nonradioactive nuclide assay.

Results

Among all cell groups, the levels of Ca²⁺, DAG, and IP3 were lowest in the control cells (P < 0.05). The Ca²⁺, DAG, and IP3 levels in the blue light + A2E-treated cells and blue light + chloroquine-treated cells were higher than those in the blue light-treated cells (P < 0.05). The Ca²⁺, DAG, and IP3 levels were highest in the blue light + A2E + chloroquine-treated group (P < 0.05). PKC activity was lowest in the control cells (P < 0.05). The PKC activity of the blue light + A2E-treated cells and blue light + chloroquine-treated cells was higher than that of the blue light-treated cells (P < 0.05), and the PKC activity of the blue light + A2E + chloroquine-treated cells was the highest (P < 0.05).

Conclusion

Blue light and A2E increased the levels of Ca²⁺, IP3, and DAG in human RPE cells and enhanced PKC activity, and blue light and A2E had a synergistic effect. Chloroquine further increased the levels of Ca²⁺, IP3, and DAG and PKC activity in RPE cells or A2E-loaded RPE cells exposed to blue light.

Modulating Macrophage Clearance of Nanoparticles: Comparison of Small-Molecule and Biologic Drugs as Pharmacokinetic Modifiers of Soft Nanomaterials

Nanomedicines show benefits in overcoming the limitations of conventional drug delivery systems by reducing side effects, toxicity, and exhibiting enhanced pharmacokinetic (PK) profiles to improve the therapeutic window of small-molecule drugs. However, upon administration, many nanoparticles (NPs) prompt induction of host innate immune responses, which in combination with other clearance pathways such as renal and hepatic, eliminate up to 99% of the administered dose. Here, we explore a drug predosing strategy to transiently suppress the mononuclear phagocyte system (MPS), subsequently improving the PK profile and biological behaviors exhibited by a model NP system [hyperbranched polymers (HBPs)] in an immunocompetent mouse model. In vitro assays allowed the identification of five drug candidates that attenuated cellular association. Predosing of lead compounds chloroquine (CQ) and zoledronic acid (ZA) further showed increased HBP retention within the circulatory system of mice, as shown by both fluorescence imaging and positron emission tomography-computed tomography. Flow cytometric evaluation of spleen and liver tissue cells following intravenous administration further demonstrated that CQ and ZA significantly reduced HBP association with myeloid cells by 23 and 16%, respectively. The results of this study support the use of CQ to pharmacologically suppress the MPS to improve NP PKs.

Identification of antimalarial targets of chloroquine by a combined deconvolution strategy of ABPP and MS-CETSA

BACKGROUND

Malaria is a devastating infectious disease that disproportionally threatens hundreds of millions of people in developing countries. In the history of anti-malaria campaign, chloroquine (CQ) has played an indispensable role, however, its mechanism of action (MoA) is not fully understood.

METHODS

We used the principle of photo-affinity labeling and click chemistry-based functionalization in the design of a CQ probe and developed a combined deconvolution strategy of activity-based protein profiling (ABPP) and mass spectrometry-coupled cellular thermal shift assay (MS-CETSA) that identified the protein targets of CQ in an unbiased manner in this study. The interactions between CQ and these identified potential protein hits were confirmed by biophysical and enzymatic assays.

RESULTS

We developed a novel clickable, photo-affinity chloroquine analog probe (CQP) which retains the antimalarial activity in the nanomole range, and identified a total of 40 proteins that specifically interacted and photo-crosslinked with CQP which was inhibited in the presence of excess CQ. Using MS-CETSA, we identified 83 candidate interacting proteins out of a total of 3375 measured parasite proteins. At the same time, we identified 8 proteins as the most potential hits which were commonly identified by both methods.

CONCLUSIONS

We found that CQ could disrupt glycolysis and energy metabolism of malarial parasites through direct binding with some of the key enzymes, a new mechanism that is different from its well-known inhibitory effect of hemozoin formation. This is the first report of identifying CQ antimalarial targets by a parallel usage of labeled (ABPP) and label-free (MS-CETSA) methods.

QTc-interval prolongation and increased risk of sudden cardiac death associated with hydroxychloroquine

AIMS:

Hydroxychloroquine and chloroquine ([hydroxy]chloroquine) are drugs used to treat malaria and rheumatological disorders and were recently suggested as beneficial for prevention and treatment of patients with coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 infection. However, longitudinal studies to assess the electrocardiographic and cardiotoxic effects of these drugs are limited. In this study, we aimed to investigate the effect of these drugs on QTc-interval and incidence of sudden cardiac death (SCD).

METHODS

We designed a longitudinal follow-up study of individuals within the prospective population-based Rotterdam Study. Eligible individuals had available data on medication and repeated ECG measurements. The study period was between 1 January 1991 and 1 January 2014. We studied on current and past use of [hydroxy]chloroquine as a time-varying exposure; high versus low daily dose of [hydroxy]chloroquine. QTc-interval duration, and the occurrence of SCD were the main outcomes. SCD was defined as an unexpected and sudden death due to cardiac arrhythmia within one hour of the onset of acute symptoms, and in patients without cardiac symptoms within 24 hours before death.

RESULTS

Among the study population of 14 594 individuals (58.8% women) with an average age of 65 years, 346 patients used [hydroxy]chloroquine at any time during follow-up. The total number of SCD cases was 609. In a multiple linear mixed model analysis, the current use of [hydroxy]chloroquine was associated with a significantly increased duration of the QTc-interval of 8.1 ms (95% CI: 3.6; 12.6) compared with non-users. The association was stronger among current-high daily dosage [15.3 (95%CI: 7.0; 23.6)] compared with current-low daily dosage [5.5 (95%CI: 0.4; 10.7)] users. In a Cox proportional hazard regression analysis, the risk of SCD was significantly higher in participants who were current users of [hydroxy]chloroquine than in non-users [adjusted hazard ratio; 3.7 (95%CI: 1.1; 12.6)].

CONCLUSIONS

In this longitudinal study, persons who received [hydroxy]chloroquine had an increased QTc-interval duration and the association was dose-dependent. [Hydroxy]chloroquine was associated with a significantly increased risk of SCD. As long as their activity against COVID-19 is controversial, cardiotoxicity is a strong argument against using these drugs to treat COVID-19 infections.

Aminoquinolines as Translational Models for Drug Repurposing: Anticancer Adjuvant Properties and Toxicokinetic-Related Features

The indiscriminate consumption of antimalarials against coronavirus disease-2019 emphasizes the longstanding clinical weapons of medicines. In this work, we conducted a review on the antitumor mechanisms of aminoquinolines, focusing on the responses and differences of tumor histological tissues and toxicity related to pharmacokinetics. This well-defined analysis shows similar mechanistic forms triggered by aminoquinolines in different histological tumor tissues and under coexposure conditions, although different pharmacological potencies also occur. These molecules are lysosomotropic amines that increase the antiproliferative action of chemotherapeutic agents, mainly by cell cycle arrest, histone acetylation, physiological changes in tyrosine kinase metabolism, inhibition of PI3K/Akt/mTOR pathways, cyclin D1, E2F1, angiogenesis, ribosome biogenesis, triggering of ATM-ATR/p53/p21 signaling, apoptosis, and presentation of tumor peptides. Their chemo/radiotherapy sensitization effects may be an adjuvant option against solid tumors, since 4-aminoquinolines induce lysosomal-mediated programmed cytotoxicity of cancer cells and accumulation of key markers, predominantly, LAMP1, p62/SQSTM1, LC3 members, GAPDH, beclin-1/Atg6, α-synuclein, and granules of lipofuscin. Adverse effects are dose-dependent, though most common with chloroquine, hydroxychloroquine, amodiaquine, and other aminoquinolines are gastrointestinal changes, blurred vision ventricular arrhythmias, cardiac arrest, QTc prolongation, severe hypoglycemia with loss of consciousness, and retinopathy, and they are more common with chloroquine than with hydroxychloroquine and amodiaquine due to pharmacokinetic features. Additionally, psychological/neurological effects were also detected during acute or chronic use, but aminoquinolines do not cross the placenta easily and low quantity is found in breast milk despite their long mean residence times, which depends on the coexistence of hepatic diseases (cancer-related or not), first pass metabolism, and comedications. The low cost and availability on the world market have converted aminoquinolines into “star drugs” for pharmaceutical repurposing, but a continuous pharmacovigilance is necessary because these antimalarials have multiple modes of action/unwanted targets, relatively narrow therapeutic windows, recurrent adverse effects, and related poisoning self-treatment. Therefore, their use must obey strict rules, ethical and medical prescriptions, and clinical and laboratory monitoring.

Repurposing of Antimicrobial Agents for Cancer Therapy: What Do We Know?

The substantial costs of clinical trials, the lengthy timelines of new drug discovery and development, along the high attrition rates underscore the need for alternative strategies for finding quickly suitable therapeutics agents. Given that most approved drugs possess more than one target tightly linked to other diseases, it encourages promptly testing these drugs in patients. Over the past decades, this has led to considerable attention for drug repurposing, which relies on identifying new uses for approved or investigational drugs outside the scope of the original medical indication. The known safety of approved drugs minimizes the possibility of failure for adverse toxicology, making them attractive de-risked compounds for new applications with potentially lower overall development costs and shorter development timelines. This latter case is an exciting opportunity, specifically in oncology, due to increased resistance towards the current therapies. Indeed, a large body of evidence shows that a wealth of non-cancer drugs has beneficial effects against cancer. Interestingly, 335 drugs are currently being evaluated in different clinical trials for their potential activities against various cancers (Redo database). This review aims to provide an extensive discussion about the anti-cancer activities exerted by antimicrobial agents and presents information about their mechanism(s) of action and stage of development/evaluation.

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

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

Repositioning of Antiparasitic Drugs for Tumor Treatment

Drug repositioning is a strategy for identifying new antitumor drugs; this strategy allows existing and approved clinical drugs to be innovatively repurposed to treat tumors. Based on the similarities between parasitic diseases and cancer, recent studies aimed to investigate the efficacy of existing antiparasitic drugs in cancer. In this review, we selected two antihelminthic drugs (macrolides and benzimidazoles) and two antiprotozoal drugs (artemisinin and its derivatives, and quinolines) and summarized the research progresses made to date on the role of these drugs in cancer. Overall, these drugs regulate tumor growth via multiple targets, pathways, and modes of action. These antiparasitic drugs are good candidates for comprehensive, in-depth analyses of tumor occurrence and development. In-depth studies may improve the current tumor diagnoses and treatment regimens. However, for clinical application, current investigations are still insufficient, warranting more comprehensive analyses.

Repurposing Chloroquine Against Multiple Diseases With Special Attention to SARS-CoV-2 and Associated Toxicity

Chloroquine and its derivatives have been used since ages to treat malaria and have also been approved by the FDA to treat autoimmune diseases. The drug employs pH-dependent inhibition of functioning and signalling of the endosome, lysosome and trans-Golgi network, immunomodulatory actions, inhibition of autophagy and interference with receptor binding to treat cancer and many viral diseases. The ongoing pandemic of COVID-19 has brought the whole world on the knees, seeking an urgent hunt for an anti-SARS-CoV-2 drug. Chloroquine has shown to inhibit receptor binding of the viral particles, interferes with their replication and inhibits "cytokine storm". Though multiple modes of actions have been employed by chloroquine against multiple diseases, viral diseases can provide an added advantage to establish the anti-SARS-CoV-2 mechanism, the in vitro and in vivo trials against SARS-CoV-2 have yielded mixed results. The toxicological effects and dosage optimization of chloroquine have been studied for many diseases, though it needs a proper evaluation again as chloroquine is also associated with several toxicities. Moreover, the drug is inexpensive and is readily available in many countries. Though much of the hope has been created by chloroquine and its derivatives against multiple diseases, repurposing it against SARS-CoV-2 requires large scale, collaborative, randomized and unbiased clinical trials to avoid false promises. This review summarizes the use and the mechanism of chloroquine against multiple diseases, its side-effects, mechanisms and the different clinical trials ongoing against "COVID-19".

Chloroquine and hydroxychloroquine in antitumor therapies based on autophagy-related mechanisms

Chloroquine (CQ) and hydroxychloroquine (HCQ) are the most common drugs used to relieve acute and chronic inflammatory diseases. In this article, we present a review about the use of CQ and HCQ in antitumor therapies based on autophagy mechanisms. These molecules break/discontinue autophagosome-lysosome fusions in initial phases and enhance antiproliferative action of chemotherapeutics. Their sensitizing effects of chemotherapy when used as an adjuvant option in clinical trials against cancer. However, human related-MDR genes are also under risk to develop chemo or radioresistance because cancer cells have ability to throw 4-aminoquinolines out from digestive vacuoles well. Additionally, they also have antitumor mechanism unrelated to autophagy, including cell death from apoptosis and necroptosis and immunomodulatory/anti-inflammatory properties. However, the link between some anticancer mechanisms, clinical efficacy and pharmacological safety has not yet been fully defined.

Exploring insights of hydroxychloroquine, a controversial drug in Covid-19: An update

The review summarizes chloroquine (CQ) and its safer derivative hydroxychloroquine (HCQ) and its utility in Covid-19. Recently this well-established drug made its way back to the headlines during the SARS-CoV-2 pandemic. This led to an upsurge in the scientific arena with multiple research and review articles along with expert opinions and commentaries. The HCQ has received mixed judgements so far about its efficacy to be used in Covid-19 patients in a limited trial conducted all across the Globe. The purpose of our article is to put forth the history, pharmacodynamics, and pharmacokinetics, along with the existing studies favouring and disapproving the role of HCQ in the treatment of Covid-19. We grouped HCQ use at three stages, this includes HCQ for i. prophylactic use by asymptomatic health workers or peoples at higher risk; ii. patients having mild symptoms; iii. patients with extreme symptoms. The review critically discusses the underlying plausible reasons and mechanisms exploring HCQ in prophylactic management or treatment of SARS-CoV-2. Furthermore, we have critically analysed the reported pharmacokinetic parameters and compiled the proponent, opponent, or neutral opinions on the use of HCQ in Covid-19. Authors discretion is to conduct more studies considering the optimal dosing regimen and pharmacokinetics assessment.

Dual Anti-Malarial and GSK3β-Mediated Cytokine-Modulating Activities of Quercetin Are Requisite of Its Potential as a Plant-Derived Therapeutic in Malaria

Although death in malaria is attributed to cerebrovascular blockage and anaemia, overwhelming cytokine production can contribute to the severity of the disease. Therefore, mitigation of dysregulated inflammatory signalling may provide further benefit for malaria treatment. Quercetin (3,3′,4′,5,7-pentahydroxyflavone) is known to inhibit glycogen synthase kinase-3β (GSK3β), a potent regulator of both pro- and anti-inflammatory effects. Quercetin is therefore a potential therapeutic to modulate the imbalanced cytokine production during malarial infection. Anti-malarial effects of quercetin were evaluated in murine models of severe and cerebral malaria using Plasmodium berghei NK65 and ANKA strains, respectively. Western blotting and analysis of cytokines were carried out to determine the GSK3β-mediated cytokine-modulating effects of quercetin in infected animals. Quercetin (25 mg/kg BW) treatment in P. berghei NK65-infected animals resulted in 60.7 ± 2.4% suppression of parasitaemia and significantly decreased serum levels of TNF-α and IFN-γ, whilst levels of IL-10 and IL-4 were elevated significantly. Western analysis revealed that pGSK3β (Ser9) increased 2.7-fold in the liver of quercetin-treated NK65-infected animals. Treatment of P. berghei ANKA-infected mice with quercetin (15 mg/kg BW) increased (2.3-fold) pGSK3β (Ser9) in the brains of infected animals. Quercetin is a potential plant-derived therapeutic for malaria on the basis that it can elicit anti-malarial and GSK3β-mediated cytokine-modulating effects.

Chloroquine ameliorates bone loss induced by d-galactose in male rats via inhibition of ERK associated osteoclastogenesis and antioxidant effect

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Cloroquine (CQ) has reduced the adverse bone changes caused by d-galactose.

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It improved bone health, switched off nuclear factor kappa-B ligand (RANKL) receptor activator activation and decreased ERK bone expression.

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CQ treatment inhibited osteoclastogenesis and consequently restored the RANKL/OPG ratio.

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CQ demonstrated an antioxidant effect in bone where it increased both catalase (CAT) and superoxide dismutase (SOD).

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CQ is a possible anti-osteoporotic agent through the suppression of osteoclastogenesis associated with ERK.

Chloroquine (CQ); a lysosomotropic agent used for decade ago as anti-malarial, was tested against aging induced osteoporosis. Osteoporosis in male rats was induced using d-galactose (D-gal) as a reducing sugar at a dose of 200 mg/kg/day; i.p. Osteoporotic rats were orally treated with CQ (10 mg/kg/day) for four successive weeks. Bone densitometry of tibia and femur were evaluated. Bone formation biomarkers; osteoprotegrin (OPG), bone specific alkaline phosphatse (BALP), and osteocalcin (OCN), and bone resorption biomarker; receptor activator of nuclear factor kappa-B ligand (RANKL), cathepsin-k (CTSK), tartrate-resistant acid phosphatase (TRAP) were estimated. Moreover, the expression of extracellular regulated kinase (ERK) in bone was determined. CQ ameliorated the bone detrimental changes induced by d-galactose. It enhanced bone health as revealed by measurement of bone densitometry, halted the activation of receptor activator of nuclear factor kappa-B ligand (RANKL) and reduced bone manifestation of ERK. Furthermore, CQ treatment abated serum cathepsin-k (CTSK) and serum tartrate-resistant acid phosphatase (TRAP) thus inhibited osteoclastogenesis and consequently restored the RANKL/OPG ratio. CQ demonstrated an antioxidant effect in bone where it increased both Catalase (CAT) and Superoxide dismutase (SOD). These CQ preserving effect in rats treated with d-galactose were confirmed by the histopathological examination. The present study points to the potential therapeutic effect of CQ as anti-osteoporotic agent possibly through its antioxidant effects and suppression of ERK associated osteoclastogenesis.

Glucose-6-phosphate dehydrogenase deficiency and hydroxychloroquine in the COVID-19 era: a mini review

The coronavirus disease 2019 (COVID-19) is until today a global health emergency. In an immense effort, effective drugs against COVID-19 are searched and intensive researches on possible repurposing of antiviral agents are performed. Since chloroquine (CQ) and hydroxychloroquine (HCQ) have shown in vitro anti- COVID-19 activities, the potential effect of CQ/HCQ to treat and/or prevent COVID-19 infection has caused global attention. However, concern regarding possible hemolysis in G6PD-deficient COVID-19 patients exists and for this reason, the association between HCQ and G6PD deficiency (G6PDD) is back in the limelight. This study aims to answer the question raised by Mastroianni et al. "Hydroxychloroquine: Culprit or Innocent Bystander in G6PD-Deficient Patients with COVID-19?", reporting all cases of HCQ in G6PD deficient COVID-19 patients published on PubMed (pubmed.ncbi.nlm.nih.gov), in addition to the Mastroianni's patient. In our opinion, after an accurate revision of these cases and responding the question raised by Mastroianni et al., we believe that it is difficult to reach a final verdict about the definitive role of HCQ in these patients. The COVID-19 pandemic has reopened attention on HCQ use and G6PDD. G6PD status is extremely important in modulating the level of reactive oxygen species and many cellular immune responses such as enhanced production of the pro-inflammatory cytokine and inflammasome activation. Since these processes are involved in COVID-19 infection, acute hemolytic anemia, a severe complication of the G6PDD, can occur in these patients. In this context, the role of HCQ, usually effective, safe, and well tolerated in G6PD deficient patients, must be redefined in these patients with COVID-19.As consequence, answering the question: "Hydroxychloroquine: Culprit or Innocent Bystander in G6PD-Deficient Patients with COVID-19?", we state that it is risky to believe that HCQ may be an "innocent bystander" in G6PD-deficient COVID-19 patients.

Spirulina platensis Alleviated the Hemotoxicity, Oxidative Damage and Histopathological Alterations of Hydroxychloroquine in Catfish (Clarias gariepinus)

The current study aims at evaluating the toxicity of hydroxychloroquine (HCQ) as a pharmaceutical residue in catfish (Clarias gariepinus) and the protective role of Spirulina platensis (SP). Four groups were used in this study: (1) a control group, (2) a group exposed to 3.16 mg/l of HCQ, (3) a group exposed to 3.16 mg/l of HCQ + 10 mg/l of SP, and (4) a group exposed to 3.16 mg/l of HCQ + 20 mg/l of SP for 15 days of exposure. The HCQ-treated group showed a significant decline in the hematological indices and glucose, total protein, and antioxidant levels in relation to the control group, whereas the HCQ-treated group showed a significant increase in the levels of creatinine, uric acid, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) as well as the percentage of poikilocytosis and nuclear abnormalities of RBCs in relation to the control group. The histopathological evaluation of the liver indicated dilation of the central vein, vacuolization, degeneration of hepatocytes and pyknotic nuclei, as well as reduction of glomeruli, dilation of Bowman's space, and degeneration of renal tubules in the kidney of the HCQ-treated group. Spirulina platensis (SP) rendered the hematological and biochemical indexes as well as antioxidant levels and the histological architecture to normal status in a dose-dependent manner. Accordingly, the current study recommends the use of SP to remedy the toxic effects of HCQ.

Calcium channel blocker amlodipine besylate therapy is associated with reduced case fatality rate of COVID-19 patients with hypertension

The coronavirus disease (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now spread to >200 countries posing a global public health concern. Patients with comorbidity, such as hypertension suffer more severe infection with elevated mortality. The development of effective antiviral drugs is in urgent need to treat COVID-19 patients. Here, we report that calcium channel blockers (CCBs), a type of antihypertensive drug that is widely used in clinics, inhibited the post-entry replication events of SARS-CoV-2 in vitro, while no in vitro anti-SARS-CoV-2 effect was observed for the two other major types of antihypertensive drugs, namely, angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers. CCB combined with chloroquine showed a significantly enhanced anti-SARS-CoV-2 efficacy. A retrospective clinical investigation on hospitalized COVID-19 patients with hypertension as the only comorbidity revealed that the CCB amlodipine besylate therapy was associated with a decreased case fatality rate. The results from this study suggest that CCB administration to COVID-19 patients with hypertension as the comorbidity might improve the disease outcome.

Chloroquine and hydroxychloroquine in the treatment of malaria and repurposing in treating COVID-19

Chloroquine (CQ) and Hydroxychloroquine (HCQ) have been commonly used for the treatment and prevention of malaria, and the treatment of autoimmune diseases for several decades. As their new mechanisms of actions are identified in recent years, CQ and HCQ have wider therapeutic applications, one of which is to treat viral infectious diseases. Since the pandemic of the coronavirus disease 2019 (COVID-19), CQ and HCQ have been subjected to a number of in vitro and in vivo tests, and their therapeutic prospects for COVID-19 have been proposed. In this article, the applications and mechanisms of action of CQ and HCQ in their conventional fields of anti-malaria and anti-rheumatism, as well as their repurposing prospects in anti-virus are reviewed. The current trials and future potential of CQ and HCQ in combating COVID-19 are discussed.

COVID-19 therapy: What weapons do we bring into battle?

Urgent treatments, in any modality, to fight SARS-CoV-2 infections are desired by society in general, by health professionals, by Estate-leaders and, mainly, by the scientific community, because one thing is certain amidst the numerous uncertainties regarding COVID-19: knowledge is the means to discover or to produce an effective treatment against this global disease. Scientists from several areas in the world are still committed to this mission, as shown by the accelerated scientific production in the first half of 2020 with over 25,000 published articles related to the new coronavirus. Three great lines of publications related to COVID-19 were identified for building this article: The first refers to knowledge production concerning the virus and pathophysiology of COVID-19; the second regards efforts to produce vaccines against SARS-CoV-2 at a speed without precedent in the history of science; the third comprehends the attempts to find a marketed drug that can be used to treat COVID-19 by drug repurposing. In this review, the drugs that have been repurposed so far are grouped according to their chemical class. Their structures will be presented to provide better understanding of their structural similarities and possible correlations with mechanisms of actions. This can help identifying anti-SARS-CoV-2 promising therapeutic agents.

New Trends for Antimalarial Drugs: Synergism between Antineoplastics and Antimalarials on Breast Cancer Cells

Chemotherapy plays a key role in breast cancer therapy, but drug resistance and unwanted side effects make the treatment less effective. We propose a new combination model that combines antineoplastic drugs and antimalarials for breast cancer therapy. Cytotoxic effects of two antineoplastic agents alone and in combination with several antimalarials on MCF-7 tumor cell line was evaluated. Different concentrations in a fixed ratio were added to the cultured cells and incubated for 48 h. Cell viability was evaluated using MTT and SRB assays. Synergism was evaluated using the Chou-Talalay method. The results indicate doxorubicin (DOX) and paclitaxel (PTX) alone at concentrations of their IC₅₀ and higher are cell growth inhibitors. Mefloquine, artesunate, and chloroquine at concentrations of their IC₅₀ demonstrate anti-cancer activity. In combination, almost all antimalarials demonstrate higher ability than DOX and PTX alone to decrease cell viability at concentrations of IC₅₀ and lower than their IC₅₀. The combination of chloroquine, artesunate and mefloquine with DOX and PTX was synergic (CI < 1). The combination of DOX and mefloquine after 48 h incubation demonstrated the highest cytotoxicity against MCF-7 cells, and the combination of DOX and artesunate was the most synergic. These results suggest antimalarials could act synergistically with DOX/PTX for breast cancer therapy.

Efficacy and safety of anti-inflammatory agents in treatment of psychotic disorders - A comprehensive systematic review and meta-analysis

OBJECTIVE

Antipsychotic effects of immunomodulating drugs have been suggested; however, a thorough, comprehensive meta-analysis on the effect and safety of anti-inflammatory add-on treatment on psychotic disorders is lacking.

METHOD

Multiple databases were searched up until February 2020. Only double-blinded, randomized, placebo-controlled clinical trials (RCTs) were included. Primary outcomes were change in total psychopathology and adverse events. Secondary outcomes included, amongst others, positive and negative symptoms, general psychopathology and cognitive domains. We performed random-effects meta-analyses estimating mean differences (MD) and standardized mean differences (SMD) for effect sizes.

RESULTS

Seventy RCTs (N = 4104) were included, investigating either primarily anti-inflammatory drugs, i.e. drugs developed for immunomodulation, such as NSAIDs, minocycline and monoclonal antibodies (k = 15), or drugs with potential anti-inflammatory properties (k = 55), e.g. neurosteroids, N-acetyl cysteine, estrogens, fatty acids, statins, and glitazones. Antipsychotics plus anti-inflammatory treatment, compared to antipsychotics plus placebo, was associated with a PANSS scale MD improvement of -4.57 (95%CI = -5.93 to -3.20) points, corresponding to a SMD effect size of -0.29 (95%CI = -0.40 to -0.19). Trials on schizophrenia (MD = -6.80; 95%CI, -9.08 to -4.52) showed greater improvement (p < 0.01) than trials also including other psychotic disorders. However, primarily anti-inflammatory drugs (MD = 4.00; 95%CI = -7.19 to -0.80) were not superior (p = 0.69) to potential anti-inflammatory drugs (MD = 4.71; 95%CI = -6.26 to -3.17). Furthermore, meta-regression found that smaller studies showed significantly larger effect sizes than the larger studies (p = 0.0085), and only 2 studies had low risk of bias on all domains. Small but significant effects were found on negative symptoms (MD = -1.29), positive symptoms (MD = -0.53), general psychopathology (MD = -1.50) and working memory (SMD = 0.21). No differences were found regarding adverse events, but only 26 studies reported hereon.

CONCLUSIONS

Anti-inflammatory add-on treatment to antipsychotics showed improvement of psychotic disorders; however, no superiority was found in primarily anti-inflammatory drugs, raising the question of the mechanism behind the effect, and treatment effect might be overestimated due to the large number of small studies.

Simultaneous Determination of Medicinal Drugs with Overlapping Profiles Contained in Low Chromatographic Resolution Data using HPLC-DAD and Multivariate Curve Resolution

Background:

The increasing demand of effective pharmaceutical products directed to fight against malaria lead to the combination of at least two antimalarial drugs. This combination aims to minimize the Plasmodium falciparum resistance which is found when the most frequently used drugs are taken individually. Within this context, proguanil hydrochloride and chloroquine phosphate which have independent modes of action are taken together to prevent malaria. This paper aims to develop a fast and powerful analytical method for the simultaneous determination of proguanil hydrochloride and chloroquine phosphate in the commercial Paludrine/Avloclor dosage forms using a multi-way chromatographic calibration based on high-performance liquid chromatography with diode array detection (HPLC-DAD) and multivariate curve resolution – alternating leastsquares (MCR-ALS).

Methods:

A rapid and powerful analytical method based on HPLC-DAD and MCR-ALS was developed for the simultaneous quantification of proguanil hydrochloride and chloroquine phosphate in the commercial Paludrine/Avloclor antimalarial drugs. An isocratic mobile phase composed by 0.2 M ammonium acetate, acetonitrile, and methanol (40:25:35) and a flow rate of 1.2 mL min-1 were employed in the chromatographic runs with an elution time about 5 min.

Results:

This approach demonstrates that chromatographic analysis may become considerably simpler and economical in terms of time, cost, and organic solvent consumption when coupled to multiway calibration models such as MCR-ALS. In fact, this multi-way chromatographic calibration based on second-order HPLC-DAD data matrices (with extremely low chromatographic resolution) and MCR-ALS allows the development of greener analytical methods for complex samples. The proposed analytical method allowed the simultaneous quantification of two antimalarial APIs present in the commercial Paludrine/Avloclor drugs with low REP values below 8% for the simultaneous determination of proguanil hydrochloride and chloroquine phosphate.

Conclusion:

The proposed multi-way chromatographic strategy can be used for routine control of pharmaceutical dosage forms. It should be highlighted that MCR-ALS allowed to: (a) achieve the second- order advantage and the quantification of analytes in the presence of uncalibrated compounds such as coeluted profile measured in different magnitude of the signal in each successive chromatographic run and significant overlapping profiles and (b) separate the contribution of several components from chromatographic runs with extremely low separation of peaks through the deconvolution of the signal obtained, performing the so-called mathematical chromatography.

Chloroquine against malaria, cancers and viral diseases

Quinoline (QN) derivatives are often used for the prophylaxis and treatment of malaria. Chloroquine (CQ), a protonated, weakly basic drug, exerts its antimalarial effect mainly by increasing pH and accumulating in the food vacuole of the parasites. Repurposing CQ is an emerging strategy for new indications. Given the inhibition of autophagy and its immunomodulatory action, CQ shows positive efficacy against cancer and viral diseases, including Coronavirus 2019 (COVID-19). Here, we review the underlying mechanisms behind the antimalarial, anticancer and antiviral effects of CQ. We also discuss the clinical evidence for the use of CQ and hydroxychloroquine (HCQ) against COVID-19.

Advances in the possible treatment of COVID-19: A review

The emergence of the global pandemic caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has put a challenge to identify or derive the therapeutics for its prevention and treatment. Despite the unprecedented advances in the modern medicinal system, currently, there are no proven effective therapies. However, rapid research on SARS-CoV-2 epidemiology help unveiling some new targets for potential drug therapies. Many drugs have been screened, and even their clinical trials are going on at an exceptional pace. Amongst these RNA-dependent RNA polymerase inhibitors (favipiravir and remdesivir) and steroids especially dexamethasone showed promising effects. The biological agents like tocilizumab, interferons, and convalescent plasma prove to be beneficial in viral clearance. Moreover, many immunomodulatory and viral S protein targeting vaccines have their ongoing clinical trials. The establishment of various in vitro and in vivo models for preclinical studies can additionally help the current research. The volume and the pace of the clinical trials launched to evaluate the safety and efficacy of various agents against coronavirus disease 2019 (COVID-19) reflect the need for high-quality evidence for various therapies to be practiced by clinicians. This study aims to sum up all the current advances in the global medicinal system against the COVID-19.

Zinc(II)-The Overlooked Éminence Grise of Chloroquine's Fight against COVID-19?

Zn(II) is an inhibitor of SARS-CoV-2's RNA-dependent RNA polymerase, and chloroquine and hydroxychloroquine are Zn(II) ionophores-this statement gives a curious mind a lot to think about. We show results of the first clinical trials on chloroquine (CQ) and hydroxychloroquine (HCQ) in the treatment of COVID-19, as well as earlier reports on the anticoronaviral properties of these two compounds and of Zn(II) itself. Other FDA-approved Zn(II) ionophores are given a decent amount of attention and are thought of as possible COVID-19 therapeutics.

Cardiovascular Safety of Potential Drugs for the Treatment of Coronavirus Disease 2019

Coronavirus disease 2019 (COVID-19) has become a global pandemic. It is still uncontrolled in most countries and no therapies are currently available. Various drugs are under investigation for its treatment. The disease is known to have worse outcomes in patients who have underlying cardiovascular disease. Chloroquine/hydroxychloroquine, azithromycin, remdesivir and lopinavir/ritonavir are currently being studied in trials and show some promise. Conduction disorders, heart failure, and mortality have been reported with the use of these drugs. It is important to have knowledge of potential cardiotoxic effects of these drugs before using them for COVID-19 patients for better allocation of healthcare resources and improvement in clinical outcomes.

Immunology of COVID-19: Current State of the Science

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide, igniting an unprecedented effort from the scientific community to understand the biological underpinning of COVID19 pathophysiology. In this Review, we summarize the current state of knowledge of innate and adaptive immune responses elicited by SARS-CoV-2 infection and the immunological pathways that likely contribute to disease severity and death. We also discuss the rationale and clinical outcome of current therapeutic strategies as well as prospective clinical trials to prevent or treat SARS-CoV-2 infection.

Revisiting hydroxychloroquine and chloroquine for patients with chronic immunity-mediated inflammatory rheumatic diseases

Hydroxychloroquine and chloroquine, also known as antimalarial drugs, are widely used in the treatment of rheumatic diseases and have recently become the focus of attention because of the ongoing COVID-19 pandemic. Rheumatologists have been using antimalarials to manage patients with chronic immune-mediated inflammatory rheumatic diseases for decades. It is an appropriate time to review their immunomodulatory and anti-inflammatory mechanisms impact on disease activity and survival of systemic lupus erythematosus patient, including antiplatelet effect, metabolic and lipid benefits. We also discuss possible adverse effects, adding a practical and comprehensive approach to monitoring rheumatic patients during treatment with these drugs.

Comprehensive Analysis of the Immune and Stromal Compartments of the CNS in EAE Mice Reveal Pathways by Which Chloroquine Suppresses Neuroinflammation

Multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) are neuroinflammatory diseases of the central nervous system (CNS), where leukocytes and CNS resident cells play important roles in disease development and pathogenesis. The antimalarial drug chloroquine (CQ) has been shown to suppress EAE by modulating dendritic cells (DCs) and Th17 cells. However, the mechanism of action by which CQ modulates EAE is far from being elucidated. Here, we comprehensively analyzed the CNS of CQ and PBS-treated EAE mice to identify and characterize the cells that are affected by CQ. Our results show that leukocytes are largely modulated by CQ and have a reduction in the expression of inflammatory markers. Intriguingly, CQ vastly modulated the CNS resident cells astrocytes, oligodendrocytes (OLs) and microglia (MG), with the latter producing IL-10 and IL-12p70. Overall, our results show a panoramic view of the cellular components that are affect by CQ and provide further evidence that drug repurposing of CQ will be beneficial to MS patients.

[Chloroquine phosphate: therapeutic drug for COVID-19]

Since the outbreak of coronavirus disease 2019 (COVID-19) in the late 2019, a variety of antiviral drugs have been used in the first-line clinical trial. The Diagnostic and Treatment Protocol for COVID-19 (Trial Version 6) in China recommends chloroquine phosphate for the first time as an anti-coronavirus trial drug. As a classic drug for treatment of malaria and rheumatism, chloroquine phosphate has been used clinically for more than 80 years, and has also shown good results in the treatment of various viral infections. As the plasma drug concentration varies greatly among different races and individuals and due to its narrow treatment window, chloroquine in likely to accumulate in the body to cause toxicity. Among the treatment regimens recommended for COVID-19, reports concerning the safety of a short-term high-dose chloroquine regimen remain scarce. In this review, the authors summarize the current research findings of chloroquine phosphate in the treatment of COVID-19, and examine the pharmacokinetic characteristics, antiviral therapy, the therapeutic mechanism and safety of chloroquine.

Autophagy: A Promising Target for Age-related Osteoporosis

Autophagy is a process the primary role of which is to clear up damaged cellular components such as long-lived proteins and organelles, thus participating in the conservation of different cells. Osteoporosis associated with aging is characterized by consistent changes in bone metabolism with suppression of bone formation as well as increased bone resorption. In advanced age, not only bone mass but also bone strength decrease in both sexes, resulting in an increased incidence of fractures. Clinical and animal experiments reveal that age-related bone loss is associated with many factors such as accumulation of autophagy, increased levels of reactive oxygen species, sex hormone deficiency, and high levels of endogenous glucocorticoids. Available basic and clinical studies indicate that age-associated factors can regulate autophagy. Those factors play important roles in bone remodeling and contribute to decreased bone mass and bone strength with aging. In this review, we summarize the mechanisms involved in bone metabolism related to aging and autophagy, supplying a theory for therapeutic targets to rescue bone mass and bone strength in older people.

Chloroquine attenuates lithium-induced NDI and proliferation of renal collecting duct cells

Lithium is widely used in psychiatry as the golden standard for more than 60 yr due to its effectiveness. However, its adverse effect has been limiting its long-term use in clinic. About 40% of patients taking lithium develop nephrogenic diabetes insipidus (NDI). Lithium can also induce proliferation of collecting duct cells, leading to microcyst formation in the kidney. Lithium was considered an autophagy inducer that might contribute to the therapeutic benefit of neuropsychiatric disorders. Thus, we hypothesized that autophagy may play a role in lithium-induced kidney nephrotoxicity. To address our hypothesis, we fed mice with a lithium-containing diet with chloroquine (CQ), an autophagy inhibitor, concurrently. Lithium-treated mice presented enhanced autophagy activity in the kidney cortex and medulla. CQ treatment significantly ameliorated lithium-induced polyuria, polydipsia, natriuresis, and kaliuresis accompanied with attenuated downregulation of aquaporin-2 and Na⁺-K⁺-2Cl^- cotransporter protein. The protective effect of CQ on aquaporin-2 protein abundance was confirmed in cultured cortical collecting duct cells. In addition, we found that lithium-induced proliferation of collecting duct cells was also suppressed by CQ as detected by proliferating cell nuclear antigen staining. Moreover, both phosphorylated mammalian target of rapamycin and β-catenin expression, which have been reported to be increased by lithium and associated with cell proliferation, were reduced by CQ. Taken together, our study demonstrated that CQ protected against lithium-induced NDI and collecting duct cell proliferation possibly through inhibiting autophagy.

Chloroquine modulates inflammatory autoimmune responses through Nurr1 in autoimmune diseases

For over a half-century the anti-malarial drug chloroquine (CQ) has been used as a therapeutic agent, alone or in combination, to treat autoimmune diseases. However, neither the underlying mechanism(s) of action nor their molecular target(s) are well defined. The orphan nuclear receptor Nurr1 (also known as NR4A2) is an essential transcription factor affecting the development and maintenance of midbrain dopaminergic neurons. In this study, using in vitro T cell differentiation models, we demonstrate that CQ activates T_REG cell differentiation and induces Foxp3 gene expression in a Nurr1-dependent manner. Remarkably, CQ appears to induce Nurr1 function by two distinct mechanisms: firstly, by direct binding to Nurr1’s ligand-binding domain and promoting its transcriptional activity and secondly by upregulation of Nurr1 expression through the CREB signaling pathway. In contrast, CQ suppressed gene expression and differentiation of pathogenic T_H17 cells. Importantly, using a valid animal model of inflammatory bowel disease (IBD), we demonstrated that CQ promotes Foxp3 expression and differentiation of T_REG cells in a Nurr1-dependent manner, leading to significant improvement of IBD-related symptoms. Taken together, these data suggest that CQ ameliorates autoimmune diseases via regulating Nurr1 function/expression and that Nurr1 is a promising target for developing effective therapeutics of human inflammatory autoimmune diseases.

The Role of Autophagy in the Resistance to BRAF Inhibition in BRAF-Mutated Melanoma

Malignant melanoma is the most aggressive and notorious skin cancer, and metastatic disease is associated with very poor long-term survival outcomes. Although metastatic melanoma patients with oncogenic mutations in the BRAF gene initially respond well to the treatment with specific BRAF inhibitors, most of them will eventually develop resistance to this targeted therapy. As a highly conserved catabolic process, autophagy is responsible for the maintenance of cellular homeostasis and cell survival, and is involved in multiple diseases, including cancer. Recent study results have indicated that autophagy might play a decisive role in the resistance to BRAF inhibitors in BRAF-mutated melanomas. In this review, we will discuss how autophagy is up-regulated by BRAF inhibitors, and how autophagy induces the resistance to these agents.

Efficacy and Safety of Topical Chloroquine in Mild to Moderate Dry Eye Disease

Purpose: To evaluate the role of topical chloroquine (CHQ) as an adjunct to topical lubricants in the management of mild-moderate dry eye disease (DED)Methods: Prospective comparative pilot study allocated 150 patients with symptoms of mild to moderate DED to receive topical CMC 0.5% three times a day (group I, n = 75) or topical CHQ 0.03% twice a day with carboxymethylcellulose (CMC) 0.5% three times a day (group II, n = 75), for three months. Primary outcome measures were ocular surface disease index (OSDI) score and conjunctival impression cytology at 3 months. Secondary outcome measures were TBUT, Schirmer's test, ocular surface staining and any adverse effects at 3 months. Follow up was performed at 1 and 3 months.Results: At three months, the OSDI score was significantly better in the CHQ group as compared with the CMC group (CMC-18.36 ± 4.03 (SD), CHQ group- 15.9 ± 5.18 (SD); p = .002). Nelson's score was 0.92 ± 0.69 (SD) in the CHQ group as compared with 1.60 ± 0.77 (SD) in the CMC group (p < .001). Abnormal impression cytology was observed in 20% cases in the CHQ group as compared with 61.3% cases in CMC group (p < .001). A significant correlation was observed between Nelson's score and OSDI (Spearman's rho correlation coefficient 0.414, p < .001). TBUT, Schirmer test and ocular surface staining were significantly better in the CHQ group (p < .001). No adverse effects were observed in any group.Conclusion: Topical chloroquine is a useful adjunct to topical lubricants in the management of DED as it decreases the underlying chronic inflammation and helps maintain ocular surface stability.

Drug repurposing for new, efficient, broad spectrum antivirals

Emerging viruses are a major threat to human health. Recent outbreaks have emphasized the urgent need for new antiviral treatments. For several pathogenic viruses, considerable efforts have focused on vaccine development. However, during epidemics infected individuals need to be treated urgently. High-throughput screening of clinically tested compounds provides a rapid means to identify undiscovered, antiviral functions for well-characterized therapeutics. Repurposed drugs can bypass part of the early cost and time needed for validation and authorization. In this review we describe recent efforts to find broad spectrum antivirals through drug repurposing. We have chosen several candidates and propose strategies to understand their mechanism of action and to determine how resistance to antivirals develops in infected cells.

Is a combination of progesterone and chloroquine more effective than either alone in the treatment of cerebral ischemic injury?

BACKGROUND

In this proof-of-concept paper, we investigated whether combination treatment with progesterone (P4) and chloroquine (CQ) would reduce ischemic injury more effectively than either agent alone in a transient middle cerebral artery occlusion (tMCAO) model in male rats.

METHODS

P4 (8 mg/kg) and CQ (25 mg/kg) were given alone or in combination beginning at different times during surgery and for 3 days post-occlusion. Locomotor activity and grip strength were evaluated as measures of impairment and recovery. Infarct size was assessed by TTC staining. Markers of autophagy (LC3 and SQSTM1/p62) and apoptosis (Bcl-2 and Bax) were evaluated with western blotting.

RESULTS

At the doses we employed, the combination was not more effective than either drug given separately on measures of grip strength or locomotor activity. However, combination therapy substantially reduced infarct size, and significantly increased Bcl-2 protein levels and suppressed Bax expression. Progesterone decreased the expression of LC3-II 24 h and SQSTM1/p62 after ischemia.

CONCLUSIONS

Our findings suggest that combination therapy with P4 and CQ is not detrimental and has a small-to-moderate additive neuroprotective effect on ischemic injury in rats without substantively affecting behavioral outcomes. CQ and P4 may help to regulate the expression of both autophagy-related and apoptosis-related proteins.

Cardiac Complications Attributed to Chloroquine and Hydroxychloroquine: A Systematic Review of the Literature

INTRODUCTION

Chloroquine and hydroxychloroquine are widely used in the long-term treatment of connective tissue disease and usually considered safe. However, chloroquine- or hydroxychloroquine-related cardiac disorder is a rare but severe adverse event, which can lead to death. This systematic review investigates cardiac complications attributed to chloroquine and hydroxychloroquine.

METHODS

PubMED, EMBASE, and Cochrane database searches were conducted using keywords derived from MeSH terms. Reports published prior to 31 July, 2017 were eligible for inclusion, without restriction to study design. Searches were also conducted on reference lists of included studies.

RESULTS

Eighty-six articles were identified, reporting individual cases or short series, providing information on 127 patients (65.4% female). A majority of patients were treated with chloroquine (58.3%), with the remaining treated with hydroxychloroquine (39.4%), or both in succession. Most patients had been treated for a long time (median 7 years, minimum 3 days; maximum 35 years) and with a high cumulative dose (median 1235 g for hydroxychloroquine and 803 g for chloroquine). Conduction disorders were the main side effect reported, affecting 85% of patients. Other non-specific adverse cardiac events included ventricular hypertrophy (22%), hypokinesia (9.4%), heart failure (26.8%), pulmonary arterial hypertension (3.9%), and valvular dysfunction (7.1%). For 78 patients reported to have been withdrawn from treatment, some recovered normal heart function (44.9%), while for others progression was unfavorable, resulting in irreversible damage (12.9%) or death (30.8%).

LIMITATIONS

The risk of cardiac complications attributed to chloroquine/hydroxychloroquine was not quantified because of the lack of randomized controlled trials and observational studies investigating the association.

CONCLUSIONS

Clinicians should be warned that chloroquine- or hydroxychloroquine-related cardiac manifestations, even conduction disorders without repercussion, may be initial manifestations of toxicity, and are potentially irreversible. Therefore, treatment withdrawal is required when cardiac manifestations are present.

Synthesis and biological evaluation of new quinoline derivatives as antileishmanial and antitrypanosomal agents

As a part of our project aimed at developing new safe chemotherapeutic agents against tropical diseases, a series of aryl derivatives of 2- and 3-aminoquinoline, some of them new compounds, was designed, synthesized, and evaluated as antiproliferative agents against Trypanosoma cruzi, the parasite responsible for American trypanosomiasis (Chagas' disease), and Leishmania mexicana, the etiological agent of Leishmaniasis. Some of them showed a remarkable activity as parasite growth inhibitors. Fluorine-containing derivatives 11b and 11c were more than twice more potent than geneticin against intracellular promastigote form of Leishmania mexicana exhibiting both IC₅₀ values of 41.9 μM. The IC₅₀ values corresponding to fluorine and chlorine derivatives 11b-d were in the same order than benznidazole against epimastigote form. These drugs are interesting examples of effective antiparasitic agents with outstanding potential not only as lead drugs but also to be used for further in vivo studies. In addition, the obtained compounds showed no toxicity in Vero cells, which makes them good candidates to control tropical diseases. Regarding the probable mode of action, assayed quinoline derivatives interacted with hemin, inhibiting its degradation and generating oxidative stress that is not counteracted by the antioxidant defense system of the parasite.