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Altulea D, Maassen S, Baranov MV, van den Bogaart G. What makes (hydroxy)chloroquine ineffective against COVID-19: insights from cell biology. J Mol Cell Biol 2021; 13:175-184. [PMID: 33693723 PMCID: PMC7989365 DOI: 10.1093/jmcb/mjab016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 02/17/2021] [Accepted: 02/24/2021] [Indexed: 12/11/2022] Open
Abstract
Since chloroquine (CQ) and hydroxychloroquine (HCQ) can inhibit the invasion and proliferation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in cultured cells, the repurposing of these antimalarial drugs was considered a promising strategy for treatment and prevention of coronavirus disease (COVID-19). However, despite promising preliminary findings, many clinical trials showed neither significant therapeutic nor prophylactic benefits of CQ and HCQ against COVID-19. Here, we aim to answer the question of why these drugs are not effective against the disease by examining the cellular working mechanisms of CQ and HCQ in prevention of SARS-CoV-2 infections.
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Affiliation(s)
- Dania Altulea
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Sjors Maassen
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Maksim V Baranov
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - G van den Bogaart
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.,Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
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Kaushik I, Ramachandran S, Prasad S, Srivastava SK. Drug rechanneling: A novel paradigm for cancer treatment. Semin Cancer Biol 2020; 68:279-290. [PMID: 32437876 DOI: 10.1016/j.semcancer.2020.03.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/15/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Cancer continues to be one of the leading contributors towards global disease burden. According to NIH, cancer incidence rate per year will increase to 23.6 million by 2030. Even though cancer continues to be a major proportion of the disease burden worldwide, it has the lowest clinical trial success rate amongst other diseases. Hence, there is an unmet need for novel, affordable and effective anti-neoplastic medications. As a result, a growing interest has sparkled amongst researchers towards drug repurposing. Drug repurposing follows the principle of polypharmacology, which states, "any drug with multiple targets or off targets can present several modes of action". Drug repurposing also known as drug rechanneling, or drug repositioning is an economic and reliable approach that identifies new disease treatment of already approved drugs. Repurposing guarantees expedited access of drugs to the patients as these drugs are already FDA approved and their safety and toxicity profile is completely established. Epidemiological studies have identified the decreased occurrence of oncological or non-oncological conditions in patients undergoing treatment with FDA approved drugs. Data from multiple experimental studies and clinical observations have depicted that several non-neoplastic drugs have potential anticancer activity. In this review, we have summarized the potential anti-cancer effects of anti-psychotic, anti-malarial, anti-viral and anti-emetic drugs with a brief overview on their mechanism and pathways in different cancer types. This review highlights promising evidences for the repurposing of drugs in oncology.
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Affiliation(s)
- Itishree Kaushik
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA
| | - Sharavan Ramachandran
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA
| | - Sahdeo Prasad
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA
| | - Sanjay K Srivastava
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA.
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Fox RI, Kang HI. Mechanism of Action of Antimalarial Drugs: Inhibition of Antigen Processing and Presentation. Lupus 2019. [DOI: 10.1177/0961203393002001031] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent studies have elucidated the steps involved in the association of antigenic peptides with major histocompatibility complex (MHC) encoded proteins and have suggested how antimalarial compounds might influence this important site of immune activation. These steps of antigen presentation in the macrophage (or other antigen-presenting cells) include: (a) the partial proteolytic degradation of endogenous and exogenous proteins into peptides within the lysosome; (b) the synthesis of MHC class II (i.e. HLA-D associated) α, β, and invariant (Ii) chains in the endoplasmic reticulum; (c) the initial association of α-Ii and β-li chains in the endoplasmic reticulum and the transport of these complexes to the primary endosome; (d) the fusion of lysosomal vacuoles and endosomal vacuoles, allowing the mixtures of lysosomal enzymes, peptides, α–Ii and β–Ii; (e) the displacement of Ii chains by peptides to form α–β–peptide complexes in the endosome; and (f) the migration of α–β–peptide complexes to the macrophage cell surface where they can stimulate CD4 T cells, resulting in release of cytokines. A low pH is required for digestion of the protein by acidic hydrolases in the lysosome, for assembly of the α–β–peptide complex and for its transport to the cell surface. Chloroquine and hydroxychloroquine are weak diprotic bases that can diffuse across the cell membrane and raise the pH within cell vesicles. This background provides the underlying basis for the theory that antimalarials may act to prevent autoimmunity by the following putative mechanism. Antimalarial compounds may: (a) stabilize the α-Ii and β-Ii interactions and prevent low-affinity peptides from forming α–β–peptide complexes; and (b) interfere with the efficient movement of α-Ii, β-Ii and α–β–peptide complexes to the correct locations within the cell cytoplasm or to the cell surfaces. Decreased presentation of autoantigenic peptides by macrophages might then lead to downregulation of autoimmune CD4+ T cells and diminish release of cytokines associated with clinical and laboratory signs of autoimmune disease.
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Affiliation(s)
- Robert I. Fox
- Department of Rheumatology, Scripps Clinic and Research Foundation, 10666 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Ho-Il Kang
- Department of Rheumatology, Scripps Clinic and Research Foundation, 10666 North Torrey Pines Road, La Jolla, California 92037, USA
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Newman SL, Smulian AG. Iron uptake and virulence in Histoplasma capsulatum. Curr Opin Microbiol 2013; 16:700-7. [DOI: 10.1016/j.mib.2013.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/28/2013] [Accepted: 09/04/2013] [Indexed: 10/26/2022]
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Henriet SSV, Jans J, Simonetti E, Kwon-Chung KJ, Rijs AJMM, Hermans PWM, Holland SM, de Jonge MI, Warris A. Chloroquine modulates the fungal immune response in phagocytic cells from patients with chronic granulomatous disease. J Infect Dis 2013; 207:1932-9. [PMID: 23482646 DOI: 10.1093/infdis/jit103] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Invasive aspergillosis is a major threat to patients with chronic granulomatous disease (CGD). Fungal pathogenesis is the result of a diminished antifungal capacity and dysregulated inflammation. A deficient NADPH-oxidase complex results in defective phagolysosomal alkalization. To investigate the contribution of defective pH regulation in phagocytes among patients with CGD during fungal pathogenesis, we evaluated the effect of the acidotropic, antimalarial drug chloroquine (CQ) on the antifungal capacity of polymorphonuclear cells (PMNs) and on the inflammatory response of peripheral blood mononuclear cells (PBMCs). Chloroquine exerted a direct pH-dependent antifungal effect on Aspergillus fumigatus and Aspergillus nidulans; it increased the antifungal activity of PMNs from patients with CGD at a significantly lower concentration, compared with the concentration for PMNs from healthy individuals; and decreased the hyperinflammatory state of PBMCs from patients with CGD, as observed by decreased tumor necrosis factor α and interleukin 1β release. Chloroquine targets both limbs of fungal pathogenesis and might be of great value in the clearance of invasive aspergillosis in patients with CGD.
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Affiliation(s)
- Stefanie S V Henriet
- Department of Pediatrics, Radboud University Nijmegen Medical Centre, The Netherlands.
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Single-Dose Pharmacokinetics of Chloroquine and its Main Metabolite in Healthy Volunteers. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/bf03259430] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Dattani JJ, Rajput DK, Moid N, Highland HN, George LB, Desai KR. Ameliorative effect of curcumin on hepatotoxicity induced by chloroquine phosphate. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2010; 30:103-109. [PMID: 21787638 DOI: 10.1016/j.etap.2010.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 04/16/2010] [Accepted: 04/19/2010] [Indexed: 05/31/2023]
Abstract
India is one of the most endemic areas, where malaria predominates and its control has become a formidable task. Chloroquine phosphate (CQ) on account of its rapid action on blood schizontocide of all the malarial parasite strains has become the most widely prescribed drug for prophylaxis and treatment of malaria. Toxicity of CQ is most commonly encountered at therapeutic and higher doses of treatment. Thus, the present study was undertaken to evaluate the protective effect of Curcumin, a herbal antioxidant obtained from Curcuma longa, on hepatic biochemical and histopathological status of CQ induced male mice. Swiss albino male mice were administered oral doses of CQ (100mg/kg body wt., 200mg/kg body wt. and 300mg/kg body wt.) and CQ+curcumin (300mg/kg body wt.+80mg/kg body wt.) for 45 days. A withdrawal of high dose treatment for 45 days was also studied. Administration of CQ brought about a significant decrease in Protein content with a decline in SDH, ATPase and ALKase activities, whereas ACPase activity was found to be significantly increased following CQ treatment. Antioxidant enzyme SOD registered a significant reduction as opposed to TBARS which was found to be elevated in a significant manner in the CQ treated groups as compared to control. Gravimetric indices (body weight and organ weight) declined significantly following CQ treatment. Administration of curcumin exhibited significant reversal of CQ induced toxicity in hepatic tissue. Protein content, SDH, ATPase, ALKase, ACPase, SOD, TBARS, body weight and organ weight were found to be comparable to that of control group after curcumin administration. Thus, obtained results led us to conclude the curative potential of curcumin against CQ induced hepatotoxicity.
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Affiliation(s)
- J J Dattani
- Department of Zoology, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat, India
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Chico RM, Pittrof R, Greenwood B, Chandramohan D. Azithromycin-chloroquine and the intermittent preventive treatment of malaria in pregnancy. Malar J 2008; 7:255. [PMID: 19087267 PMCID: PMC2632633 DOI: 10.1186/1475-2875-7-255] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 12/16/2008] [Indexed: 11/12/2022] Open
Abstract
In the high malaria-transmission settings of sub-Saharan Africa, malaria in pregnancy is an important cause of maternal, perinatal and neonatal morbidity. Intermittent preventive treatment of malaria in pregnancy (IPTp) with sulphadoxine-pyrimethamine (SP) reduces the incidence of low birth-weight, pre-term delivery, intrauterine growth-retardation and maternal anaemia. However, the public health benefits of IPTp are declining due to SP resistance. The combination of azithromycin and chloroquine is a potential alternative to SP for IPTp. This review summarizes key in vitro and in vivo evidence of azithromycin and chloroquine activity against Plasmodium falciparum and Plasmodium vivax, as well as the anticipated secondary benefits that may result from their combined use in IPTp, including the cure and prevention of many sexually transmitted diseases. Drug costs and the necessity for external financing are discussed along with a range of issues related to drug resistance and surveillance. Several scientific and programmatic questions of interest to policymakers and programme managers are also presented that would need to be addressed before azithromycin-chloroquine could be adopted for use in IPTp.
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Affiliation(s)
- R Matthew Chico
- Department of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E7HT, UK.
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Abstract
Intracellular pathogenic organisms such as salmonellae and shigellae are able to evade the effects of many antibiotics because the drugs are not able to penetrate the plasma membrane. In addition, these bacteria may be able to transfer genes within cells while protected from the action of drugs. The primary mode by which virulence and antibiotic resistance genes are spread is bacterial conjugation. Salmonellae have been shown to be competent for conjugation in the vacuoles of cultured mammalian cells. We now show that the conjugation machinery is also functional in the mammalian cytosol. Specially constructed Escherichia coli strains expressing Shigella flexneri plasmid and chromosomal virulence factors for escape from vacuoles and synthesizing the invasin protein from Yersinia pseudotuberculosis to enhance cellular entry were able to enter 3T3 cells and escape from the phagocytic vacuole. One bacterial strain (the donor) of each pair to be introduced sequentially into mammalian cells had a conjugative plasmid. We found that this plasmid could be transferred at high frequency. Conjugation in the cytoplasm of cells may well be a general phenomenon.
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Thorogood N, Atwal S, Mills W, Jenner M, Lewis DA, Cavenagh JD, Agrawal SG. The risk of antimalarials in patients with renal failure. Postgrad Med J 2008; 83:e8. [PMID: 18057166 DOI: 10.1136/pgmj.2007.063735] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We present here a patient with end stage renal failure who received two weeks antimalarial prophylaxis at full dose leading to life threatening toxicity with severe acute megaloblastic anaemia, symptomatic pancytopenia and exfoliative dermatitis. Prompt recognition and treatment can rapidly reverse these fatal effects but more importantly, education of patients before travel is imperative in preventing such events.
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Affiliation(s)
- N Thorogood
- Princess Alexandra Hospital, Harlow, Essex, UK
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Cornelissen B, Hu M, McLarty K, Costantini D, Reilly RM. Cellular penetration and nuclear importation properties of 111In-labeled and 123I-labeled HIV-1 tat peptide immunoconjugates in BT-474 human breast cancer cells. Nucl Med Biol 2007; 34:37-46. [PMID: 17210460 DOI: 10.1016/j.nucmedbio.2006.10.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 10/26/2006] [Accepted: 10/30/2006] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Our objective was to compare the cell penetration and nuclear importation properties of 111In-labeled and 123I-labeled immunoconjugates (ICs) composed of 16-mer peptides (GRKKRRQRRRPPQGYG) derived from HIV-1 transactivator of transcription (tat) protein and anti-mouse IgG (mIgG) in BT-474 breast cancer (BC) cells. METHODS [111In]tat ICs were constructed by site-specific conjugation of tat peptides to NaIO4(-)-oxidized carbohydrates in the Fc domain of diethylenetriaminepentaacetic-acid-modified anti-mIgG antibodies. Immunoreactivity against mIgG was assessed in a competition assay. The kinetics of the accumulation of [111In]anti-mIgG-tat IC and [123I]anti-mIgG-tat ICs in BT-474 cells and the elimination of radioactivity from cells, cytoplasm or nuclei were determined. The effects of excess tat peptides or NH4Cl (an inhibitor of endosomal acidification) on cellular uptake and nuclear importation of [111In]anti-mIgG-tat were measured. RESULTS [111In]anti-mIgG-tat was >97% radiochemically pure and exhibited preserved immunoreactivity with mIgG epitopes. [123I]Anti-mIgG-tat penetrated BT-474 cells more rapidly than [111In]anti-mIgG-tat ICs and achieved a 1.5-fold to a 2-fold higher uptake in cells and nuclei. Cell penetration and nuclear uptake of [111In]anti-mIgG-tat were inhibited by excess tat peptides and NH4Cl. Elimination of radioactivity from BT-474 cells and nuclei was more rapid and complete for 123I-labeled than for 111In-labeled anti-mIgG-tat ICs. CONCLUSION Tat peptides derived from HIV-1 tat protein promoted the penetration and nuclear uptake of radioactivity following the incubation of 111In-labeled and 123I-labeled anti-mIgG antibodies with BT-474 human BC cells. 111In-labeled tat ICs are feasible for inserting radionuclides into cancer cells with potential for targeting intracellular and, particularly, nuclear epitopes for imaging and/or radiotherapeutic applications.
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Affiliation(s)
- Bart Cornelissen
- Division of Nuclear Medicine, University Health Network, Toronto, ON, Canada M5S 3M2
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Dias-Melicio LA, Moreira AP, Calvi SA, Soares AMVDC. Chloroquine inhibits Paracoccidioides brasiliensis survival within human monocytes by limiting the availability of intracellular iron. Microbiol Immunol 2006; 50:307-14. [PMID: 16625052 DOI: 10.1111/j.1348-0421.2006.tb03798.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanisms used by Paracoccidioides brasiliensis(Pb 18) to survive into monocytes are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens, including P. brasiliensis, whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Chloroquine, by virtue of its basic properties, has been shown to prevent release of iron from holotransferrin by raising endocytic and lysosomal pH, and thereby interfering with normal iron metabolism. Then, in view of this, we have studied the effects of CHLOR on P. brasiliensis multiplication in human monocytes and its effect on the murine paracoccidioidomycosis. CHLOR induced human monocytes to kill P. brasiliensis. The effect of CHLOR was reversed by FeNTA, an iron compound that is soluble at neutral to alkaline pH, but not by holotransferrin, which releases iron only in an acidic environment. CHLOR treatment of Pb 18-infected BALB/c mice significantly reduced the viable fungi recovery from lungs, during three different periods of evaluation, in a dose-dependent manner. This study demonstrates that iron is of critical importance to the survival of P. brasiliensis yeasts within human monocytes and the CHLOR treatment in vitro induces Pb 18 yeast-killing by monocytes by restricting the availability of intracellular iron. Besides, the CHLOR treatment in vivo significantly reduces the number of organisms in the lungs of Pb-infected mice protecting them from several infections. Thus, CHLOR was effective in the treatment of murine paracoccidioidomycosis, suggesting the potential use of this drug in patients' treatment.
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Affiliation(s)
- Luciane Alarcão Dias-Melicio
- Department of Microbiology and Immunology, Biosciences Institute, São Paulo State University, Botucatu, S.P, Brazil
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Newman SL, Gootee L, Hilty J, Morris RE. Human macrophages do not require phagosome acidification to mediate fungistatic/fungicidal activity against Histoplasma capsulatum. THE JOURNAL OF IMMUNOLOGY 2006; 176:1806-13. [PMID: 16424211 DOI: 10.4049/jimmunol.176.3.1806] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Histoplasma capsulatum (Hc) is a facultative intracellular fungus that modulates the intraphagosomal environment to survive within macrophages (Mphi). In the present study, we sought to quantify the intraphagosomal pH under conditions in which Hc yeasts replicated or were killed. Human Mphi that had ingested both viable and heat-killed or fixed yeasts maintained an intraphagosomal pH of approximately 6.4-6.5 over a period of several hours. These results were obtained using a fluorescent ratio technique and by electron microscopy using the 3-(2,4-dinitroanilo)-3'-amino-N-methyldipropylamine reagent. Mphi that had ingested Saccharomyces cerevisae, a nonpathogenic yeast that is rapidly killed and degraded by Mphi, also maintained an intraphagosomal pH of approximately 6.5 over a period of several hours. Stimulation of human Mphi fungicidal activity by coculture with chloroquine or by adherence to type 1 collagen matrices was not reversed by bafilomycin, an inhibitor of the vacuolar ATPase. Human Mphi cultured in the presence of bafilomycin also completely degraded heat-killed Hc yeasts, whereas mouse peritoneal Mphi digestion of yeasts was completely reversed in the presence of bafilomycin. However, bafilomycin did not inhibit mouse Mphi fungistatic activity induced by IFN-gamma. Thus, human Mphi do not require phagosomal acidification to kill and degrade Hc yeasts, whereas mouse Mphi do require acidification for fungicidal but not fungistatic activity.
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Affiliation(s)
- Simon L Newman
- Department of Medicine, Division of Infectious Diseases, University of Cincinnati College of Medicine, OH 45267, USA.
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. OO, . RA, . OA, . OO. Incidence of Chloroquine Induced Oxidative Stress in the Blood of Rabbit. INT J PHARMACOL 2005. [DOI: 10.3923/ijp.2006.121.125] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
The antimalarials, mainly chloroquine and hydroxychloroquine, derive from the quinoleine core of quinine. Their initial therapeutic indication was the treatment of malaria attacks but, because of anti-inflammatory and immuno-modulatory activities, they have been since used to treat many other pathologies, in particular dermatological ones. For some of these pathologies, lupus or porphyria cutanea tarda for example, the use of these molecules is based on obvious scientific evidence. For other pathologies (cutaneous sarcoidosis, polymyositis, polymorphous light eruption...), the data on the medical literature corroborating the daily clinical practice are extremely poor. Their toxicity is limited. Their most common toxic effects are gastrointestinal (mild nausea or diarrhea) or mucocutaneous (reversible skin or mucosal pigmentation). Their most serious and dreaded side effect, retinopathy, can be largely prevented by using amounts of APS adapted to the weight of the patients. The recommended "safe" daily dose for hydroxychloroquine is 6.5 mg per kilogramme of body weight and for chloroquine 4 mg per kilogramme of body weight. However, at 6- to 12 months intervals, follow-up eye examinations should be performed.
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Affiliation(s)
- L Fardet
- Service de Dermatologie, Hôpital Henri Mondor, 51, avenue Maréchal de Lattre de Tassigny, 94000 Créteil
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Khan MA, Jabeen R, Mohammad O. Prophylactic role of liposomized chloroquine against murine cryptococcosis less susceptible to fluconazole. Pharm Res 2005; 21:2207-12. [PMID: 15648251 DOI: 10.1007/s11095-004-7672-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE The prophylactic role of liposomized chloroquine (lip-CQ) has been assessed against less susceptible Cryptococcus neoformans infection in murine model. METHODS In the current study, we investigated the antifungal activity of lip-CQ against C. neoformans in macrophages cell line (J 774) and murine model. Mice were pretreated with free as well as liposomized formulations of CQ at various doses. The anticryptococcal activity of fluconazole was compared in mice with or without CQ pretreatment. The efficacy of CQ prophylaxis was assessed by survival as well as colony forming units (cfu) in brain and lungs of treated mice. RESULTS Fluconazole alone was not found significantly effective against C. neoformans in both in vitro and in vivo studies. However, the antifungal activity of fluconazole increases in chloroquine-pretreated mice. Lip-CQ was found to be more effective in comparison to the same dose of free chloroquine in reducing fungal burden from macrophages in vitro and lungs and brain of C. neoformans infected mice. CONCLUSIONS The enhanced prophylactic activity of lip-CQ seems due to rapid uptake of drug-containing liposomes by macrophages. The liposome-mediated accumulation of CQ in macrophages makes the environment unfavorable (alkaline) for the intracellular multiplication of C. neoformans. Moreover, the increased incidence of multi-drug resistance and diversity of pathogenic microorganisms inhibited or killed by CQ makes it the drug of choice for prophylactic therapy.
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Fritzsche M. Chronic Lyme borreliosis at the root of multiple sclerosis – is a cure with antibiotics attainable? Med Hypotheses 2005; 64:438-48. [PMID: 15617845 DOI: 10.1016/j.mehy.2004.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Accepted: 09/17/2004] [Indexed: 11/15/2022]
Abstract
Apart from its devastating impact on individuals and their families, multiple sclerosis (MS) creates a huge economic burden for society by mainly afflicting young adults in their most productive years. Although effective strategies for symptom management and disease modifying therapies have evolved, there exists no curative treatment yet. Worldwide, MS prevalence parallels the distribution of the Lyme disease pathogen Borrelia (B.) burgdorferi, and in America and Europe, the birth excesses of those individuals who later in life develop MS exactly mirror the seasonal distributions of Borrelia transmitting Ixodes ticks. In addition to known acute infections, no other disease exhibits equally marked epidemiological clusters by season and locality, nurturing the hope that prevention might ultimately be attainable. As minocycline, tinidazole and hydroxychloroquine are reportedly capable of destroying both the spirochaetal and cystic L-form of B. burgdorferi found in MS brains, there emerges also new hope for those already afflicted. The immunomodulating anti-inflammatory potential of minocycline and hydroxychloroquine may furthermore reduce the Jarisch Herxheimer reaction triggered by decaying Borrelia at treatment initiation. Even in those cases unrelated to B. burgdorferi, minocycline is known for its beneficial effect on several factors considered to be detrimental in MS. Patients receiving a combination of these pharmaceuticals are thus expected to be cured or to have a longer period of remission compared to untreated controls. Although the goal of this rational, cost-effective and potentially curative treatment seems simple enough, the importance of a scientifically sound approach cannot be overemphasised. A randomised, prospective, double blinded trial is necessary in patients from B. burgdorferi endemic areas with established MS and/or Borrelia L-forms in their cerebrospinal fluid, and to yield reasonable significance within due time, the groups must be large enough and preferably taken together in a multi-centre study.
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Affiliation(s)
- Markus Fritzsche
- Clinic for Internal and Geographical Medicine, Soodstrasse 13, 8134 Adliswil, Switzerland.
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Park J, Choi K, Jeong E, Kwon D, Benveniste EN, Choi C. Reactive oxygen species mediate chloroquine-induced expression of chemokines by human astroglial cells. Glia 2004; 47:9-20. [PMID: 15139008 DOI: 10.1002/glia.20017] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have previously demonstrated that chloroquine may evoke inflammatory responses in the central nervous system by inducing expression of pro-inflammatory cytokines by astroglial cells. In this study, we further examined the molecular mechanism responsible for chloroquine-induced activation of NF-kappaB and subsequent expression of chemokines by astroglial cells. We observed that (1) chloroquine induced expression of chemokines such as CCL2 and CXCL8 in a dose- and time-dependent manner in human astroglial cells; (2) other lysosomotropic agents such as ammonium chloride and bafilomycin A1 had minimal effects on chemokine expression; (3) inhibition of NF-kappaB by MG-132 and TPCK suppressed chloroquine-induced mRNA expression of chemokines; (4) chloroquine increased the intracellular level of reactive oxygen species (ROS) in a dose- and time-dependent manner by human astroglial cells, but not by monocytic/microglial cells; (5) chloroquine-induced increase of intracellular ROS level was suppressed by pre-incubation with diphenyl iodonium (DPI) and N-acetyl cysteine (NAC); and (6) inhibition of chloroquine-induced ROS production by DPI or NAC suppressed chloroquine-mediated activation of NF-kappaB and subsequent mRNA expression of chemokines in astroglial cells. These results collectively suggest that chloroquine generates ROS, which is responsible for NF-kappaB activation and subsequent expression of pro-inflammatory chemokines in human astroglial cells.
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Affiliation(s)
- Jinseu Park
- Department of Genetic Engineering, College of Natural Science, Hallym University, Chunchon, Korea
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Park J, Kwon D, Choi C, Oh JW, Benveniste EN. Chloroquine induces activation of nuclear factor-kappaB and subsequent expression of pro-inflammatory cytokines by human astroglial cells. J Neurochem 2003; 84:1266-74. [PMID: 12614327 DOI: 10.1046/j.1471-4159.2003.01623.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chloroquine, an antimalarial lysosomotropic base, is known for its anti-inflammatory effects and therefore used for treatment of autoimmune diseases. Given its anti-inflammatory effects, it has been under clinical trials to modify neurodegenerative processes. In this study, we examined whether chloroquine has an anti-inflammatory effect in the CNS by determining the in vitro effects of chloroquine on LPS-induced expression of cytokines by glial cells. We observed that (i) chloroquine augmented LPS-induced expression of pro-inflammatory cytokines such as lymphotoxin (LT)-beta, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, IL-1beta and IL-6 in human astroglial cells, while the same treatment suppressed LPS-induced expression of cytokines in monocytic and microglial cells; (ii) chloroquine alone induced expression of pro-inflammatory cytokines in a dose- and time-dependent manner in astroglial cells; (iii) other lysosomotropic agents such as ammonium chloride and bafilomycin A1 had minimal effects on cytokine expression; and (iv) chloroquine induced the activation of nuclear factor-kappa B in astroglial cells, which is a required component of chloroquine induction of cytokines. These results suggest that chloroquine may evoke either anti- or pro-inflammatory responses in the CNS depending on the cellular context.
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Affiliation(s)
- Jinseu Park
- Department of Cell Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
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21
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Abstract
Haeme metabolism remains a vulnerable problem for the intraerythrocytic Plasmodium which catabolises haemoglobin as a source of amino acids in an acidic, oxygen-rich lysosome-like digestive vacuole. Haeme monomer, capable of generating oxygen radicals, transforms into an inert crystal named malarial pigment or haemozoin by forming unique dimers that then crystalise. Laveran first described pigmented bodies in humans to define a protozoan as the aetiologic agent of malaria. The trail of malaria pigment enabled Ross to implicate the mosquito in the life cycle of Plasmodium. In 1991, Slater and Cerami postulated a unique iron-carboxylate bond between two haemes in haemozoin crystals based on infrared and X-ray spectroscopy data. Additionally, parasite extracts were shown to possess a 'haeme polymerase' enzymatic activity as the process of crystal formation was then termed. Importantly, the quinolines, such as choloroquine, inhibit haemozoin formation. A Plasmodium falciparum derived histidine-rich protein II, which binds haeme and initiates haemozoin formation, is present in the digestive vacuole. Pfhistidine-rich protein II and Pfhistidine-rich protein III are sufficient, but not necessary for haemozoin formation as a laboratory clone lacking both still makes the haeme crystals. The reduvid bug, and the Schistosoma and Haemoproteus genera also make haemozoin. Recently, Bohle and coworkers used X-ray diffraction to document the iron-carboxylate bond in intact desiccated parasites and to show that a Fe1-O41 head to tail haeme dimer is the unit building block of haemozoin. The role of the Plasmodium histidine-rich protein family members, lipids or potential novel proteins in the exact molecular assembly of the large molecular weight haeme crystals in the protein rich digestive vacuole needs to be solved. Accurate experimental determination of the role of haemozoin formation and inhibition as the target of chloroquine is fundamental to determination of the mechanism of quinoline drug action and resistance. The enhanced understanding of the biosynthetic pathway leading to haemozoin formation using functional proteomic tools and the mechanisms through which existing antimalarial drugs affect Plasmodium haeme chemistry will help design improved chaemotherapeutic agents.
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Affiliation(s)
- David J Sullivan
- The Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
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Taramelli D, Tognazioli C, Ravagnani F, Leopardi O, Giannulis G, Boelaert JR. Inhibition of intramacrophage growth of Penicillium marneffei by 4-aminoquinolines. Antimicrob Agents Chemother 2001; 45:1450-5. [PMID: 11302809 PMCID: PMC90487 DOI: 10.1128/aac.45.5.1450-1455.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antimicrobial activities of chloroquine (CQ) and several 4-aminoquinoline drugs were tested against Penicillium marneffei, an opportunistic fungus that invades and grows inside macrophages and causes disseminated infection in AIDS patients. Human THP1 and mouse J774 macrophages were infected in vitro with P. marneffei conidia and treated with different doses of drugs for 24 to 48 h followed by cell lysis and the counting of P. marneffei CFU. CQ and amodiaquine exerted a dose-dependent inhibition of fungal growth, whereas quinine and artemisinin were fungistatic and not fungicidal. The antifungal activity of CQ was not due to an impairment of fungal iron acquisition in that it was not reversed by the addition of iron nitrilotriacetate, FeCl3, or iron ammonium citrate. Perl's staining indicated that CQ did not alter the ability of J774 cells to acquire iron from the medium. Most likely, CQ's antifungal activity is due to an increase in the intravacuolar pH and a disruption of pH-dependent metabolic processes. Indeed, we demonstrate that (i) bafilomycin A1 and ammonium chloride, two agents known to alkalinize intracellular vesicles by different mechanisms, were inhibitory as well and (ii) a newly synthesized 4-amino-7-chloroquinoline molecule (compound 9), lacking the terminal amino side chain of CQ that assists in drug accumulation, did not inhibit P. marneffei growth. These results suggest that CQ has a potential for use in prophylaxis of P. marneffei infections in human immunodeficiency virus-infected patients in countries where P. marneffei is endemic.
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Affiliation(s)
- D Taramelli
- Istituto di Microbiologia, Universita di Milano, Milan, Italy.
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Francis SE, Sullivan DJ, Goldberg DE. Hemoglobin metabolism in the malaria parasite Plasmodium falciparum. Annu Rev Microbiol 2001; 51:97-123. [PMID: 9343345 DOI: 10.1146/annurev.micro.51.1.97] [Citation(s) in RCA: 542] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hemoglobin degradation in intraerythrocytic malaria parasites is a vast process that occurs in an acidic digestive vacuole. Proteases that participate in this catabolic pathway have been defined. Studies of protease biosynthesis have revealed unusual targeting and activation mechanisms. Oxygen radicals and heme are released during proteolysis and must be detoxified by dismutation and polymerization, respectively. The quinoline antimalarials appear to act by preventing sequestration of this toxic heme. Understanding the disposition of hemoglobin has allowed identification of essential processes and metabolic weakpoints that can be exploited to combat this scourge of mankind.
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Affiliation(s)
- S E Francis
- Howard Hughes Medical Institute, Department of Molecular Microbiology and Barnes-Jewish Hospital, St. Louis, Missouri 63110, USA
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Wedi B, Novacovic V, Koerner M, Kapp A. Chronic urticaria serum induces histamine release, leukotriene production, and basophil CD63 surface expression--inhibitory effects ofanti-inflammatory drugs. J Allergy Clin Immunol 2000; 105:552-60. [PMID: 10719307 DOI: 10.1067/mai.2000.104939] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND A role of potential histamine-releasing autoantibodies against the high-affinity IgE receptor on the surface of basophils and mast cells is discussed in the pathogenesis of chronic urticaria. This so-called autoimmune urticaria may be diagnosed by a positive intracutaneous autologous serum skin test, which is found in about 30% of patients with chronic urticaria. OBJECTIVE Our purpose was, first, to compare the effect of complement-inactivated sera of 20 patients with chronic urticaria and positive autologous serum skin tests, 20 patients with chronic urticaria and negative skin tests, and 20 control subjects without chronic urticaria (10 atopic and 10 nonatopic subjects) and, second, to analyze the effect of anti-inflammatory drugs on the serum activity. METHODS The following assay systems were used: release of histamine in whole blood samples, surface expression of the activation marker CD63 on basophils, and sulfidoleukotriene de novo production in leukocyte suspensions. Whole blood, basophils, and leukocyte suspensions were obtained from a nonatopic and an atopic donor. RESULTS Sera of patients with autologous serum skin test positive chronic urticaria resulted not only in significantly increased histamine release compared with skin test-negative chronic urticaria sera but also in a significant higher induction of basophil CD63 surface expression and sulfidoleukotriene de novo production. However, serum activity was neither characteristic for chronic urticaria nor for chronic urticaria with a positive autologous serum skin test. Preincubation with dapsone, chloroquine, and lidocaine dose dependently resulted in a significant reduction of all histamine release, CD63 expression, and sulfidoleukotriene production. In addition, mizolastine was able to inhibit serum-induced sulfidoleukotriene production. CONCLUSION Further studies investigating the in vivo effect of these drugs will have to clarify their role in the management of the subset of patients with chronic urticaria demonstrating serum-induced inflammatory effects.
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Affiliation(s)
- B Wedi
- Department of Dermatology, Hannover Medical University, Hannover, Germany
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25
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Affiliation(s)
- R Wolf
- Department of Dermatology, Tel-Aviv Sourasky Medical Center, Ichilov Hospital, Israel
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Boelaert JR, Sperber K, Piette J. Chloroquine exerts an additive in vitro anti-HIV type 1 effect when associated with didanosine and hydroxyurea. AIDS Res Hum Retroviruses 1999; 15:1241-7. [PMID: 10505672 DOI: 10.1089/088922299310133] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Several groups, including ours, have reported that chloroquine (CQ) or its analog hydroxychloroquine has anti-HIV-1 activity both in vitro and in vivo. We studied in vitro whether the addition of CQ to the combination of hydroxyurea (HU) plus didanosine (ddI) had an additive effect in inhibiting the replication of HIV-1. Therefore both the H-9 T lymphocytic cell line and the U-937 promonocytic cell line as well as primary T cells and monocytes were infected with HIV-1 and then treated with HU at 0.2 mM and ddI at 1 microM and varying concentrations of CQ. Addition of CQ resulted in an additional inhibition of HIV-1 replication, as assessed by reverse transcriptase (RT) activity, with a CQ EC50 of 0.4-0.9 microM for the cell lines and of 0.2-0.9 microM for the primary cells. Similarly, addition of CQ further inhibited HIV-1 replication in U-1 cells stimulated either with LPS or H2O2 and in ACH-2 cells stimulated either with PMA or H2O2, with CQ EC50 values of 0.1 and 1 microM, respectively. Under the experimental conditions used, CQ induced neither toxicity nor apoptosis in the H-9 and U-937 cells. This in vitro additive anti-HIV-1 activity of CQ, in combination with HU + ddI, supports the idea that this triple regimen should be studied in clinical trials. It may become of particular interest to HIV-1-infected individuals from the developing world, in view of the low cost of both CQ and HU.
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Affiliation(s)
- J R Boelaert
- Unit for Renal and Infectious Diseases, Algemeen Ziekenhuis St-Jan, Brugge, Belgium.
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27
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Abstract
Proteolytic enzymes seem to play important roles in the life cycles of all medically important protozoan parasites, including the organisms that cause malaria, trypanosomiasis, leishmaniasis, amebiasis, toxoplasmosis, giardiasis, cryptosporidiosis and trichomoniasis. Proteases from all four major proteolytic classes are utilized by protozoans for diverse functions, including the invasion of host cells and tissues, the degradation of mediators of the immune response and the hydrolysis of host proteins for nutritional purposes. The biochemical and molecular characterization of protozoan proteases is providing tools to improve our understanding of the functions of these enzymes. In addition, studies in multiple systems suggest that inhibitors of protozoan proteases have potent antiparasitic effects. This review will discuss recent advances in the identification and characterization of protozoan proteases, in the determination of the function of these enzymes, and in the evaluation of protease inhibitors as potential antiprotozoan drugs.
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Affiliation(s)
- P J Rosenthal
- Department of Medicine, San Francisco General Hospital, University of California 94143-0811, USA
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Legssyer R, Ward RJ, Crichton RR, Boelaert JR. Effect of chronic chloroquine administration on iron loading in the liver and reticuloendothelial system and on oxidative responses by the alveolar macrophages. Biochem Pharmacol 1999; 57:907-11. [PMID: 10086324 DOI: 10.1016/s0006-2952(98)00368-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability of chloroquine to alter iron loading in the liver, spleen, and alveolar macrophages was investigated in iron-loaded or -depleted rats. Chloroquine significantly reduced incorporation of iron into the liver, spleen, and alveolar macrophages of animals loaded in vivo with iron dextran. The ability of these macrophages to respond to oxidative stress was assayed by their capacity to release reactive nitrogen intermediates after lipopolysaccharide (LPS) stimulation. A significant reduction in nitrite release was observed in primary cultures of macrophages isolated from chloroquine/iron dextran-administered rats in comparison to macrophages lavaged from rats iron-loaded alone. Macrophages isolated from iron-deficient rats showed a significant increase in nitrite after LPS stimulation, whereas nitrite release in the macrophages lavaged from the rats which had also received chloroquine during the iron depletion regime was much lower. These results indicate that the use of agents which decrease the iron content and diminish the oxidative response of the cell to altered iron status may be of therapeutic value in patients with iron loading, particularly of the reticuloendothelial system.
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Affiliation(s)
- R Legssyer
- Unité de Biochimie, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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29
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Ghigo D, Aldieri E, Todde R, Costamagna C, Garbarino G, Pescarmona G, Bosia A. Chloroquine stimulates nitric oxide synthesis in murine, porcine, and human endothelial cells. J Clin Invest 1998; 102:595-605. [PMID: 9691096 PMCID: PMC508920 DOI: 10.1172/jci1052] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nitric oxide (NO) is a free radical involved in the regulation of many cell functions and in the expression of several diseases. We have found that the antimalarial and antiinflammatory drug, chloroquine, is able to stimulate NO synthase (NOS) activity in murine, porcine, and human endothelial cells in vitro: the increase of enzyme activity is dependent on a de novo synthesis of some regulatory protein, as it is inhibited by cycloheximide but is not accompanied by an increased expression of inducible or constitutive NOS isoforms. Increased NO synthesis is, at least partly, responsible for chloroquine-induced inhibition of cell proliferation: indeed, NOS inhibitors revert the drug-evoked blockage of mitogenesis and ornithine decarboxylase activity in murine and porcine endothelial cells. The NOS-activating effect of chloroquine is dependent on its weak base properties, as it is exerted also by ammonium chloride, another lysosomotropic agent. Both compounds activate NOS by limiting the availability of iron: their stimulating effects on NO synthesis and inhibiting action on cell proliferation are reverted by iron supplementation with ferric nitrilotriacetate, and are mimicked by incubation with desferrioxamine. Our results suggest that NO synthesis can be stimulated in endothelial cells by chloroquine via an impairment of iron metabolism.
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Affiliation(s)
- D Ghigo
- Department of Genetics, Biology, and Biochemistry, University of Torino, 10126 Torino, Italy.
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31
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Charous BL, Halpern EF, Steven GC. Hydroxychloroquine improves airflow and lowers circulating IgE levels in subjects with moderate symptomatic asthma. J Allergy Clin Immunol 1998; 102:198-203. [PMID: 9723661 DOI: 10.1016/s0091-6749(98)70086-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Although antiinflammatory therapy is accepted as the cornerstone of asthma treatment, available systemic immunosuppressive agents are not widely used because of justified concerns over potential toxicity. Hydroxychloroquine (HCQ) is a well-tolerated, safe immunomodulating drug, with proven efficacy in rheumatic diseases and known actions that suggest potential utility in the treatment of asthma. OBJECTIVE We sought to assess the effectiveness of HCQ in subjects with moderate symptomatic asthma. METHODS Symptomatic asthmatic subjects receiving stable doses of at least 6 puffs of inhaled corticosteroid per day with daily need for beta2-adrenergic agonists were studied. After baseline run-in, these subjects were randomized to 30 weeks of HCQ (n = 8) or placebo (n = 9). Objective measures included change from baseline mean FEV1, morning and evening peak flows, beta2-agonist use, IgE level, and need for rescue corticosteroids. Subjective symptom scores from bidaily diaries were also obtained. RESULTS In the treatment group, mean FEV1 at the last 2 visits on therapy increased by 10.8% (P < .05), morning peak flows rose 16.2% (P < .03), evening peak flows rose 14.2% (P < .04), and beta2-agonist use fell 18.6% (P < .03). Mean IgE level declined 48% from 240 to 125 IU/mL. (P < .05). In the placebo group no significant change in these parameters occurred. Comparison of changes in these objective measures between the treatment and placebo groups failed to reach significance in the small population studied. Corticosteroid rescue interventions were required in 4 patients receiving placebo and 2 receiving HCQ. HCQ was well tolerated without notable side effects. CONCLUSIONS Although the size of our sample population precludes definitive conclusions, these findings extend previous open-label observations. The late improvement in the HCQ group is consistent with its known slow onset of action. Further studies are warranted to confirm the antiasthmatic and antiallergic effects of HCQ and to investigate its potential as a disease-modifying agent.
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Affiliation(s)
- B L Charous
- Allergy and Respiratory Care Center, Milwaukee Medical Clinic, Wis 53217, USA
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Karres I, Kremer JP, Dietl I, Steckholzer U, Jochum M, Ertel W. Chloroquine inhibits proinflammatory cytokine release into human whole blood. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:R1058-64. [PMID: 9575969 DOI: 10.1152/ajpregu.1998.274.4.r1058] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Excessive synthesis and release of proinflammatory cytokines during endotoxemia causes severe pathophysiological derangements and organ failure. Because the lysosomotropic agent chloroquine has been effective in the treatment of diseases associated with increased secretion of proinflammatory cytokines such as malaria or rheumatoid arthritis, this study evaluates the potential effect of chloroquine on endotoxin-induced cytokinemia using human whole blood from healthy volunteers. Chloroquine revealed a dose-dependent inhibitory effect on endotoxin-induced secretion of tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 that was associated with reduced cytokine mRNA expression. Moreover, ammonia and methylamine, which react as weak bases like chloroquine, reduced synthesis and secretion of proinflammatory cytokines. These data indicate a potent anti-inflammatory effect of chloroquine on endotoxin-induced synthesis of proinflammatory cytokines that may be due to its weak base effect. Thus chloroquine may be of therapeutic benefit not only, during chronic inflammation but also in diseases that are related to bacteria-induced inflammation.
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Affiliation(s)
- I Karres
- Division of Trauma Surgery, University Hospital of Zurich, Switzerland
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Marzella L, Lee HK. Chapter 5 Role of lysosomes in cell injury. PRINCIPLES OF MEDICAL BIOLOGY A MULTI-VOLUME WORK, VOLUME 13 1998. [PMCID: PMC7149001 DOI: 10.1016/s1569-2582(98)80007-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Lysosomes are acidic intracellular vacuoles of heterogeneous shape, size, and content. Lysosomes contain hydrolytic enzymes that degrade proteins, lipids, carbohydrates, and nucleic acids derived from intracellular (through autophagy) and extracellular (through heterophagy) sources. Lysosomal degradation regulates several physiological cell functions. These include turnover of cellular organelles and extracellular constituents; amino acid and glucose homeostasis; processing of proteins; lipid metabolism; cell growth, differentiation, and involution; host defenses against microorganisms and other pathogens; and removal of necrotic and foreign material from the circulation and from tissues. Lysosomal degradation also plays an important role in the pathophysiology of acute and chronic cell injury, inflammation and repair, and tumor growth and metastasis. The participation of the lysosomes in the specific types of cell injury we have discussed is due to altered regulation of one or more of the following processes: turnover of cellular organelles by autophagic degradation; levels and activities of lysosomal hydrolases; levels of intracellular and extracellular lysosomal hydrolase inhibitors; transport of degradation products from the lysosomal matrix to the cytosol; permeability of the lysosomal membrane to hydrolases; lysosomal vacuolar acidification; transport of degradable substrates and of pathogens to the lysosomes; transport and processing of secretory proteins and lysosomal hydrolases during biogenesis; traffic and fusion of lysosomal vacuoles and vesicles; secretion of lysosomal hydrolases; and accumulation of metals, particularly iron, acidotropic agents, and undegraded and/or undegradable materials in lysosomes.
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Lieske JC, Norris R, Swift H, Toback FG. Adhesion, internalization and metabolism of calcium oxalate monohydrate crystals by renal epithelial cells. Kidney Int 1997; 52:1291-301. [PMID: 9350652 DOI: 10.1038/ki.1997.454] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The interaction between crystals that nucleate in the nephron lumen and tubular cells could be an important determinant of renal calcification. Kidney epithelial cells in monolayer culture (BSC-1 line), used to model the tubule, rapidly bound and internalized crystals of calcium oxalate monohydrate (COM), the most common constituent of renal stones. Transmission and scanning electron microscopy, enzyme histochemistry, and kinetic analysis of [14C]-labeled crystals were used to study the interaction between renal cells and COM crystals. Electron microscopy revealed that adherent crystals on the apical cell surface can serve as sites for aggregation of additional crystals. Enhanced binding of exogenous crystals to plasma membrane domains overlying internalized crystals was observed for at least 24 hours after the initial cell-crystal interaction. Following internalization, crystals appeared to dissolve within lysosomal inclusion bodies during the ensuing five to seven weeks. Over this time, many cells still containing crystals clustered together in the monolayer. These observations suggest that adhesion and internalization can promote crystal retention in the nephron, whereas intracellular dissolution of crystals may serve as an important, hitherto unrecognized defense against pathologic renal calcification.
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Affiliation(s)
- J C Lieske
- Department of Medicine, University of Chicago, Illinois, USA.
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35
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Levitz SM, Harrison TS, Tabuni A, Liu X. Chloroquine induces human mononuclear phagocytes to inhibit and kill Cryptococcus neoformans by a mechanism independent of iron deprivation. J Clin Invest 1997; 100:1640-6. [PMID: 9294133 PMCID: PMC508346 DOI: 10.1172/jci119688] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Infections due to Cryptococcus neoformans are common in AIDS patients. We investigated the effect of chloroquine, which raises the pH of phagolysosomes, on the anticryptococcal activity of mononuclear phagocytes. C. neoformans multiplied within monocyte-derived macrophages (MDM) in the absence of chloroquine but were killed with the addition of chloroquine. Ammonium chloride was also beneficial, suggesting that effects were mediated by alkalinizing the phagolysosome. Chloroquine inhibits growth of other intracellular pathogens by limiting iron availability. However, chloroquine-induced augmentation of MDM anticryptococcal activity was unaffected by iron nitriloacetate, demonstrating that chloroquine worked by a mechanism independent of iron deprivation. There was an inverse correlation between growth of C. neoformans in cell-free media and pH, suggesting that some of the effect of chloroquine on the anticryptococcal activity of MDM could be explained by relatively poor growth at higher pH. Chloroquine enhanced MDM anticryptococcal activity against all tested cryptococcal strains except for one large-capsule strain which was not phagocytosed. Positive effects of chloroquine were also seen in monocytes from both HIV-infected and -uninfected donors. Finally, chloroquine was therapeutic in experimental cryptococcosis in outbred and severe combined immunodeficient mice. Thus, chloroquine enhances the activity of mononuclear phagocytes against C. neoformans by iron-independent, pH-dependent mechanisms and is therapeutic in murine models of cryptococcosis. Chloroquine might have clinical utility for the prophylaxis and treatment of human cryptococcosis.
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Affiliation(s)
- S M Levitz
- The Evans Memorial Department of Clinical Research and the Department of Medicine, Boston Medical Center, Boston, Massachusetts 02118, USA.
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Mazzolla R, Barluzzi R, Brozzetti A, Boelaert JR, Luna T, Saleppico S, Bistoni F, Blasi E. Enhanced resistance to Cryptococcus neoformans infection induced by chloroquine in a murine model of meningoencephalitis. Antimicrob Agents Chemother 1997; 41:802-7. [PMID: 9087493 PMCID: PMC163798 DOI: 10.1128/aac.41.4.802] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Although the pathogenesis of cerebral cryptococcosis is poorly understood, local immune cells, such as microglia and astrocytes, likely play a critical role in containing infection. Chloroquine (CQ) is a weak base that accumulates within acidic vacuoles and increases their pH. Consequently, proteolytic activity of lysosomal enzymes and intracellular iron release/availability are impaired, resulting in decreased availability of nutrients crucial to microorganism survival and growth in the host. We found that CQ enhances BV2 microglial-cell-mediated anticryptococcal activity in vitro. The phenomenon is (i) evident when both unopsonized and opsonized microorganisms are used and (ii) mimicked by NH4Cl, another weak base, and by bafilomycin A1, an inhibitor of vacuolar-type H+-ATPases. In vivo, intracerebral administration of CQ before lethal local challenge with Cryptococcus neoformans results in a significant augmentation of median survival time and a marked reduction of yeast growth in the brain and is associated with the enhancement of local interleukin 1beta (IL-1beta) and IL-6 mRNA transcripts. Overall, these results provide the first evidence that CQ enhances anticryptococcal host defenses.
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Affiliation(s)
- R Mazzolla
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy
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Srivastava IK, Rottenberg H, Vaidya AB. Atovaquone, a broad spectrum antiparasitic drug, collapses mitochondrial membrane potential in a malarial parasite. J Biol Chem 1997; 272:3961-6. [PMID: 9020100 DOI: 10.1074/jbc.272.7.3961] [Citation(s) in RCA: 261] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
At present, approaches to studying mitochondrial functions in malarial parasites are quite limited because of the technical difficulties in isolating functional mitochondria in sufficient quantity and purity. We have developed a flow cytometric assay as an alternate means to study mitochondrial functions in intact erythrocytes infected with Plasmodium yoelii, a rodent malaria parasite. By using a very low concentration (2 nM) of a lipophilic cationic fluorescent probe, 3,3'dihexyloxacarbocyanine iodide, we were able to measure mitochondrial membrane potential(DeltaPsim) in live intact parasitized erythrocytes through flow cytometry. The accumulation of the probe into parasite mitochondria was dependent on the presence of a membrane potential since inclusion of carbonyl cyanide m-chlorophenylhydrazone, a protonophore, dissipated the membrane potential and abolished the probe accumulation. We tested the effect of standard mitochondrial inhibitors such as myxothiazole, antimycin, cyanide and rotenone. All of them except rotenone collapsed the DeltaPsim and inhibited respiration. The assay was validated by comparing the EC50 of these compounds for inhibiting DeltaPsim and respiration. This assay was used to investigate the effect of various antimalarial drugs such as chloroquine, tetracycline and a broad spectrum antiparasitic drug atovaquone. We observed that only atovaquone collapsed DeltaPsim and inhibited parasite respiration within minutes after drug treatment. Furthermore, atovaquone had no effect on mammalian DeltaPsim. This suggests that atovaquone, shown to inhibit mitochondrial electron transport, also depolarizes malarial mitochondria with consequent cellular damage and death.
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Affiliation(s)
- I K Srivastava
- Department of Microbiology and Immunology, MCP Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19102-1192, USA
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Abstract
Erythrocytic malaria parasites transport large quantities of erythrocyte cytoplasm to an acidic food vacuole, where hemoglobin is degraded. Globin is hydrolysed to free amino acids, which are subsequently incorporated into parasite proteins. Potentially toxic heme moieties are polymerized to hemozoin and also probably provide necessary parasite iron. Our understanding of the precise mechanisms of hemoglobin processing is incomplete. However, it is clear that hemoglobin catabolism and related events in the malarial food vacuole are the likely targets of both important antimalarial drugs and of promising new compounds. Thus, a more precise characterization of the metabolism of hemoglobin and iron by malaria parasites should expedite the development of new modes of antimalarial chemotherapy.
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Affiliation(s)
- P J Rosenthal
- Department of Medicine, San Francisco General Hospital, University of California 94143, USA.
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Ornstein MH, Sperber K. The antiinflammatory and antiviral effects of hydroxychloroquine in two patients with acquired immunodeficiency syndrome and active inflammatory arthritis. ARTHRITIS AND RHEUMATISM 1996; 39:157-61. [PMID: 8546725 DOI: 10.1002/art.1780390122] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To report the antiinflammatory and antiviral effects of hydroxychloroquine (HCQ) treatment in 2 patients with AIDS and inflammatory arthritis. METHODS Two patients with AIDS and inflammatory arthritis were treated with HCQ, which was given in a loading dose of 600 mg/day. The maintenance dosage was calculated to remain below 6.5 mg/kg/day. Both patients had initial T cell subset studies; 1 patient, had serum and plasma collected before and after 1 year of HCQ treatment. Assays were performed for T cell subsets, recoverable human immunodeficiency virus type 1 (HIV-1) RNA, mitogen- and antigen-specific proliferation, and interleukin-6 (IL-6) levels. New studies on the use of HCQ as an anti-HIV-1 agent are reviewed. RESULTS Both patients had a dramatic decrease in their arthritis activity. Neither patient required immunosuppressive therapy or developed an opportunistic infection. In the patient who was studied after 1 year of therapy, there was a 1-log decrease in recoverable HIV-1 RNA, improved mitogen- and antigen-specific immune responses, and a large decrease in the IL-6 level while taking HCQ. Recent in vitro and in vivo assays in patients with HIV infection have shown similar antiviral and antiinflammatory effects from HCQ. CONCLUSION HCQ may exert simultaneous anti-inflammatory and antiviral effects in patients with HIV infection and inflammatory arthritis. If larger studies confirm this observation, it may be the drug of choice in this population of patients.
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Affiliation(s)
- M H Ornstein
- Division of the Rheumatology, Mount Sinai Medical Center, New York, NY 10029, USA
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Newman SL, Gootee L, Stroobant V, van der Goot H, Boelaert JR. Inhibition of growth of Histoplasma capsulatum yeast cells in human macrophages by the iron chelator VUF 8514 and comparison of VUF 8514 with deferoxamine. Antimicrob Agents Chemother 1995; 39:1824-9. [PMID: 7486926 PMCID: PMC162833 DOI: 10.1128/aac.39.8.1824] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Histoplasma capsulatum requires intracellular iron to survive and multiply within human and murine macrophages (M phi). Thus, iron chelators may be useful compounds in the treatment of histoplasmosis. In the present study we compared the efficacies of five different iron chelators with deferoxamine (DEF) for their capacity to inhibit the growth of H. capsulatum yeast cells in culture medium and within human M phi. Of the agents tested, only one, VUF 8514, a 2,2'-bipyridyl analog, was found to be effective. VUF 8514 inhibited the growth of yeast cells in tissue culture medium and within M phi in a dose-response fashion. In tissue culture medium, the 50% effective dose (ED50) of VUF 8514 was 30 nM and the ED50 of DEF was 1 mM. In human M phi, the ED50 of VUF 8514 was 520 nM and the ED50 of DEF was 4 mM. Thus, VUF 8514 was effective at a concentration 7.7 x 10(3)-fold lower than DEF in inhibiting the growth of yeast cells in M phi. Inhibition of the intracellular growth of yeast cells by VUF 8514 was reversed by holotransferrin and iron nitriloacetate, an iron compound that is soluble at neutral to alkaline pH. Thus, VUF 8514 inhibits the intracellular growth of yeast cells by acting as an iron chelator rather than through its capacity as a weak base. These data suggest that the hydroxamic acid siderophore of H. capsulatum yeast cells competes successfully for iron against some iron chelators but not others and that VUF 8514 may be a potential therapeutic agent for the treatment of histoplasmosis.
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Affiliation(s)
- S L Newman
- Department of Medicine, University of Cincinnati College of Medicine, Ohio 45267, USA
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41
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Crider B, Xie X, Stone D. Bafilomycin inhibits proton flow through the H+ channel of vacuolar proton pumps. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32447-x] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Newman SL, Gootee L, Brunner G, Deepe GS. Chloroquine induces human macrophage killing of Histoplasma capsulatum by limiting the availability of intracellular iron and is therapeutic in a murine model of histoplasmosis. J Clin Invest 1994; 93:1422-9. [PMID: 8163646 PMCID: PMC294155 DOI: 10.1172/jci117119] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We investigated the role of intracellular iron on the capacity of Histoplasma capsulatum (Hc) yeasts to multiply within human macrophages (Mphi). Coculture of Hc-infected Mphi with the iron chelator deferoxamine suppressed the growth of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by iron-free transferrin (apotransferrin). Chloroquine, which prevents release of iron from transferrin by raising endocytic and lysosomal pH, induced human Mphi to kill Hc. The effect of chloroquine was reversed by iron nitriloacetate, an iron compound that is soluble at neutral to alkaline pH, but not by holotransferrin, which releases iron only in an acidic environment. Chloroquine (40-120 mg/kg) given intraperitoneally for 6 d to Hc-infected C57BL/6 mice significantly reduced the growth of Hc in a dose-dependent manner. At 120 mg/kg there was a 17- and 15-fold reduction (P < 0.01) in CFU in spleens and livers, respectively. The therapeutic effect of chloroquine also correlated with the length of treatment. As little as 2 d of chloroquine therapy (120 mg/kg), when started at day 5 after infection, reduced CFU in the spleen by 50%. Treatment with chloroquine for 10 d after a lethal inoculum of Hc protected six of nine mice; all control mice were dead by day 11 (P = 0.009). This study demonstrates that: (a) iron is of critical importance to the survival and multiplication of Hc yeasts in human Mphi; (b) in vitro, chloroquine induces Mphi killing of Hc yeasts by restricting the availability of intracellular iron; and (c) in vivo, chloroquine significantly reduces the number of organisms in the spleens and livers of Hc-infected mice and can protect mice from a lethal inoculum of Hc yeasts. Thus, chloroquine may be effective in the treatment of active histoplasmosis and also may be useful in preventing relapse of histoplasmosis in patients with acquired immunodeficiency syndromes.
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Affiliation(s)
- S L Newman
- Department of Medicine, University of Cincinnati College of Medicine, Ohio 45267
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43
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Levine DS. Immune modulating therapies for idiopathic inflammatory bowel diseases. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1994; 25:171-234. [PMID: 8204501 DOI: 10.1016/s1054-3589(08)60432-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- D S Levine
- Department of Medicine, University of Washington, Seattle 98195
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Abstract
The antimalarial agents chloroquine and hydroxychloroquine have been used widely for the treatment of rheumatoid arthritis and systemic lupus erythematosus. These compounds lead to improvement of clinical and laboratory parameters, but their slow onset of action distinguishes them from glucocorticoids and nonsteroidal antiinflammatory agents. Chloroquine and hydroxychloroquine increase pH within intracellular vacuoles and alter processes such as protein degradation by acidic hydrolases in the lysosome, assembly of macromolecules in the endosomes, and posttranslation modification of proteins in the Golgi apparatus. It is proposed that the antirheumatic properties of these compounds results from their interference with "antigen processing" in macrophages and other antigen-presenting cells. Acidic cytoplasmic compartments are required for the antigenic protein to be digested and for the peptides to assemble with the alpha and beta chains of MHC class II proteins. As a result, antimalarials diminish the formation of peptide-MHC protein complexes required to stimulate CD4+ T cells and result in down-regulation of the immune response against autoantigenic peptides. Because this mechanism differs from other antirheumatic drugs, antimalarials are well suited to complement these other compounds in combination drug therapy.
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Affiliation(s)
- R I Fox
- Department of Rheumatology, Scripps Clinic and Research Foundation, La Jolla, CA 92037
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45
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Eissenberg LG, Goldman WE, Schlesinger PH. Histoplasma capsulatum modulates the acidification of phagolysosomes. J Exp Med 1993; 177:1605-11. [PMID: 8496679 PMCID: PMC2191039 DOI: 10.1084/jem.177.6.1605] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The phagolysosome is perhaps the most effective antimicrobial site within macrophages due both to its acidity and to its variety of hydrolytic enzymes. Few species of pathogens survive and multiply in these vesicles. However, one strategy for microbial survival would be to induce a higher pH within these organelles, thus interfering with the activity of many lysosomal enzymes. Altering the intravesicular milieu might also profoundly influence antigen processing, antimicrobial drug delivery, and drug activity. Here we report the first example of an organism proliferating within phagolysosomes that maintain a relatively neutral pH for a sustained period of time. We inoculated P388D1 macrophages with fluorescein isothiocyanate (FITC)-labeled Histoplasma capsulatum or zymosan. Using the ratio of fluorescence excitations at 495 and 450 nm, we determined that vesicles containing either virulent or avirulent FITC-labeled H. capsulatum yeasts had a pH one to two units higher than vesicles containing either zymosan or methanol-killed H. capsulatum. The difference in pH remained stable for at least 5.5 h postinoculation. Longer-term studies using cells preincubated with acridine orange indicated that phagolysosomes containing live Histoplasma continued to maintain a relatively neutral pH for at least 30 h. Many agents raise the pH of multiple vesicles within the same cell. In contrast, H. capsulatum affects only the phagolysosome in which it is located; during coinoculation of cells with unlabeled Histoplasma and labeled zymosan, organelles containing zymosan still acidified normally. Similarly, unlabeled zymosan had no influence on the elevated pH of vesicles housing labeled Histoplasma. Thus, zymosan and Histoplasma were segregated into separate phagolysosomes that responded independently to their phagocytized contents. This localized effect might reflect an intrinsic difference between phagosomes housing the two particle types, active buffering by the microbe, or altered ion transport across the phagolysosomal membrane such that acidification is inhibited.
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Affiliation(s)
- L G Eissenberg
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
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Sperber K, Kalb TH, Stecher VJ, Banerjee R, Mayer L. Inhibition of human immunodeficiency virus type 1 replication by hydroxychloroquine in T cells and monocytes. AIDS Res Hum Retroviruses 1993; 9:91-8. [PMID: 8427717 DOI: 10.1089/aid.1993.9.91] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Chloroquine and its analogue hydroxychloroquine (HCQ) have been shown to inhibit a variety of viral infections including influenza and adenovirus through blockade of viral entry via inhibition of endosomal acidification. We have extended these observations to human immunodeficiency virus type 1 (HIV-1) infection utilizing primary T cells and monocytes, a T cell line (CEM), and a monocytic cell line (U-937). HCQ inhibited HIV-1 replication (> 75%), as measured by reverse transcriptase activity, in the primary T cells and monocytes as well as the T cell and monocytic cell lines. HCQ itself had no anti-reverse transcriptase activity and was not toxic to the cells at concentrations inhibitory to viral replication. Intracytoplasmic staining with an anti-p24 antibody, 24 h after infection, revealed the presence of intracytoplasmic virus, suggesting that the drug does not block viral entry. The production of steady-state HIV-1 mRNA was not affected by HCQ in that comparable levels of HIV-1 mRNA could be detected by Northern blot analysis and by in situ hybridization in both the HCQ-treated and untreated cells. However, HCQ does appear to affect production of infectious HIV-1 virions because viral isolates from HCQ-treated cells could not infect target CEM cells. These data suggest that HCQ may be useful adjunctive therapy in the treatment of HIV-1 infection.
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Affiliation(s)
- K Sperber
- Division of Clinical Immunology, Mount Sinai Medical Center, New York, NY 10029
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Affiliation(s)
- A F Slater
- Picower Institute for Medical Research, Manhasset, New York 11030
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48
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Slater AF, Cerami A. Inhibition by chloroquine of a novel haem polymerase enzyme activity in malaria trophozoites. Nature 1992; 355:167-9. [PMID: 1729651 DOI: 10.1038/355167a0] [Citation(s) in RCA: 431] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The incidence of human malaria has increased during the past 20 years; 270 million people are now estimated to be infected with the parasite. An important contribution to this increase has been the appearance of malaria organisms resistant to quinoline-containing antimalarials such as chloroquine and quinine. These drugs accumulate in the acid food vacuoles of the intraerythrocytic-stage malaria parasite, although the mechanism of their specific toxicity in this organelle is uncertain. The primary function of the food vacuole is the proteolysis of ingested red cell haemoglobin to provide the growing parasite with essential amino acids. Haemoglobin breakdown in the food vacuole releases haem, which if soluble can damage biological membranes and inhibit a variety of enzymes. Rather than degrading or excreting the haem, the parasite has evolved a novel pathway for its detoxification by incorporating it into an insoluble crystalline material called haemozoin or malaria pigment. These crystals form in the food vacuole of the parasite concomitant with haemoglobin degradation, where they remain until the infected red cell bursts. The structure of haemozoin comprises a polymer of haems linked between the central ferric ion of one haem and a carboxylate side-group oxygen of another. This structure does not form spontaneously from either free haem or haemoglobin under physiological conditions, and the biochemistry of its formation is unclear. Here we report the identification and characterization of a haem polymerase enzyme activity from extracts of Plasmodium falciparum trophozoites, and show that this enzyme is inhibited by quinoline-containing drugs such as chloroquine and quinine. This provides a possible explanation for the highly stage-specific antimalarial properties of these drugs.
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Affiliation(s)
- A F Slater
- Picower Institute for Medical Research, Manhasset, New York 11030
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Krogstad DJ, Gluzman IY, Herwaldt BL, Schlesinger PH, Wellems TE. Energy dependence of chloroquine accumulation and chloroquine efflux in Plasmodium falciparum. Biochem Pharmacol 1992; 43:57-62. [PMID: 1531176 DOI: 10.1016/0006-2952(92)90661-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Chloroquine inhibits the growth of susceptible malaria parasites at low (nanomolar) concentrations because of an energy-requiring drug-concentrating mechanism in the parasite secondary lysosome (food vacuole) which is dependent on the acidification of that vesicle. Chloroquine resistance results from another energy-requiring process: efflux of chloroquine from the resistant parasite with a half-time of 2 min. Chloroquine efflux is inhibited reversibly by the removal of metabolizable substrate (glucose); it is also reduced by the ATPase inhibitor vanadate. These results suggest that chloroquine efflux is an energy-requiring process dependent on the generation and hydrolysis of ATP. Chloroquine efflux cannot be explained by differences in drug accumulation between chloroquine-susceptible and -resistant parasites because the 40-50-fold difference in initial efflux rates between -susceptible and -resistant parasites is unchanged when both parasites contain the same amount of chloroquine. Although chloroquine efflux is phenotypically similar to the efflux of anticancer drugs from multidrug-resistant (mdr) mammalian cells, it is not linked to either of the mdr-like genes of the parasite.
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Affiliation(s)
- D J Krogstad
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110
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Nilsson JR. Does chloroquine, an antimalarial drug, affect autophagy in Tetrahymena pyriformis? THE JOURNAL OF PROTOZOOLOGY 1992; 39:9-16. [PMID: 1560421 DOI: 10.1111/j.1550-7408.1992.tb01278.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effect of chloroquine (CQ) on autophagy was studied in starved Tetrahymena pyriformis. When a proliferating Tetrahymena culture is transferred to a starvation medium, autophagy commences although cells most advanced in the cell cycle will divide. The drug was added to 1-h starved cells at different pH values because CQ affects pH dependently. The CQ concentration blocking all cell divisions was determined as the lowest toxic, but sublethal, concentration. Hence, the highest tolerated concentrations at pH 6.8, 7.1, and 7.7 were 1.0, 0.3, and 0.03 mM CQ, respectively. Lower CQ concentrations had a dose-dependent effect on cell increment and higher concentrations induced cell mortality. Rates of cell motility and decreases in cell volume were affected by the drug, while the capacity for endocytosis was unaffected in low concentrations but affected dose dependently in high concentrations. Light microscopically, all drug-treated cells contained small refractive bodies, but in toxic concentrations they also contained conspicuously large vacuoles. After 1 h and 4 h in CQ, fine structure analysis showed autophagosomes with electron-dense material in cells in tolerated concentrations and of enlarged size, but decreased number, in toxic concentrations. The contents of autophagosomes revealed cell organelles in different stages of disintegration. The conclusion is that the drug enhances autophagy in Tetrahymena in a pH-, dose-, and time-dependent manner.
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Affiliation(s)
- J R Nilsson
- Institute of Cell Biology and Anatomy, University of Copenhagen, Denmark
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