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Bārzdiņa A, Plotniece A, Sobolev A, Pajuste K, Bandere D, Brangule A. From Polymeric Nanoformulations to Polyphenols-Strategies for Enhancing the Efficacy and Drug Delivery of Gentamicin. Antibiotics (Basel) 2024; 13:305. [PMID: 38666981 PMCID: PMC11047640 DOI: 10.3390/antibiotics13040305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/29/2024] Open
Abstract
Gentamicin is an essential broad-spectrum aminoglycoside antibiotic that is used in over 40 clinical conditions and has shown activity against a wide range of nosocomial, biofilm-forming, multi-drug resistant bacteria. Nevertheless, the low cellular penetration and serious side effects of gentamicin, as well as the fear of the development of antibacterial resistance, has led to a search for ways to circumvent these obstacles. This review provides an overview of the chemical and pharmacological properties of gentamicin and offers six different strategies (the isolation of specific types of gentamicin, encapsulation in polymeric nanoparticles, hydrophobization of the gentamicin molecule, and combinations of gentamicin with other antibiotics, polyphenols, and natural products) that aim to enhance the drug delivery and antibacterial activity of gentamicin. In addition, factors influencing the synthesis of gentamicin-loaded polymeric (poly (lactic-co-glycolic acid) (PLGA) and chitosan) nanoparticles and the methods used in drug release studies are discussed. Potential research directions and future perspectives for gentamicin-loaded drug delivery systems are given.
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Affiliation(s)
- Ance Bārzdiņa
- Department of Pharmaceutical Chemistry, Riga Stradins University, 21 Konsula Str., LV-1007 Riga, Latvia; (A.P.)
- Baltic Biomaterials Centre of Excellence, Headquarters at Riga Technical University, LV-1007 Riga, Latvia
| | - Aiva Plotniece
- Department of Pharmaceutical Chemistry, Riga Stradins University, 21 Konsula Str., LV-1007 Riga, Latvia; (A.P.)
- Latvian Institute of Organic Synthesis, 21 Aizkraukles Str., LV-1006 Riga, Latvia; (A.S.); (K.P.)
| | - Arkadij Sobolev
- Latvian Institute of Organic Synthesis, 21 Aizkraukles Str., LV-1006 Riga, Latvia; (A.S.); (K.P.)
| | - Karlis Pajuste
- Latvian Institute of Organic Synthesis, 21 Aizkraukles Str., LV-1006 Riga, Latvia; (A.S.); (K.P.)
| | - Dace Bandere
- Department of Pharmaceutical Chemistry, Riga Stradins University, 21 Konsula Str., LV-1007 Riga, Latvia; (A.P.)
- Baltic Biomaterials Centre of Excellence, Headquarters at Riga Technical University, LV-1007 Riga, Latvia
| | - Agnese Brangule
- Department of Pharmaceutical Chemistry, Riga Stradins University, 21 Konsula Str., LV-1007 Riga, Latvia; (A.P.)
- Baltic Biomaterials Centre of Excellence, Headquarters at Riga Technical University, LV-1007 Riga, Latvia
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2
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Jana S, Rajasekaran P, Haldimann K, Vasella A, Böttger EC, Hobbie SN, Crich D. Synthesis of Gentamicins C1, C2, and C2a and Antiribosomal and Antibacterial Activity of Gentamicins B1, C1, C1a, C2, C2a, C2b, and X2. ACS Infect Dis 2023; 9:1622-1633. [PMID: 37481733 PMCID: PMC10425985 DOI: 10.1021/acsinfecdis.3c00233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Indexed: 07/25/2023]
Abstract
Complementing our earlier syntheses of the gentamicins B1, C1a, C2b, and X2, we describe the synthesis of gentamicins C1, C2, and C2a characterized by methyl substitution at the 6'-position, and so present an alternative access to previous chromatographic methods for accessing these sought-after compounds. We describe the antiribosomal activity of our full set of synthetic gentamicin congeners against bacterial ribosomes and hybrid ribosomes carrying the decoding A site of the human mitochondrial, A1555G mutant mitochondrial, and cytoplasmic ribosomes and establish structure-activity relationships with the substitution pattern around ring I to antiribosomal activity, antibacterial resistance due to the presence of aminoglycoside acetyl transferases acting on the 6'-position in ring I, and literature cochlear toxicity data.
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Affiliation(s)
- Santanu Jana
- Department
of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
| | - Parasuraman Rajasekaran
- Department
of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
| | - Klara Haldimann
- Institute
of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8006 Zürich, Switzerland
| | - Andrea Vasella
- Organic
Chemistry Laboratory, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Erik C. Böttger
- Institute
of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8006 Zürich, Switzerland
| | - Sven N. Hobbie
- Institute
of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8006 Zürich, Switzerland
| | - David Crich
- Department
of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
- Department
of Chemistry, University of Georgia, 302 East Campus Road, Athens, Georgia 30602, United States
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3
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Wagner MC, Sandoval RM, Yadav SPS, Campos SB, Rhodes GJ, Phillips CL, Molitoris BA. Lrpap1 (RAP) Inhibits Proximal Tubule Clathrin Mediated and Clathrin Independent Endocytosis, Ameliorating Renal Aminoglycoside Nephrotoxicity. KIDNEY360 2023; 4:591-605. [PMID: 36848531 PMCID: PMC10278819 DOI: 10.34067/kid.0000000000000094] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 01/31/2023] [Indexed: 03/01/2023]
Abstract
Key Points Proximal tubule endocytosis of toxins often leads to nephrotoxicity. Inhibition of endocytosis with receptor-associated protein may serve as a clinical approach to reduce or eliminate kidney damage from a potential nephrotoxin. Background Proximal tubules (PTs) are exposed to many exogenous and endogenous nephrotoxins that pass through the glomerular filter. This includes many small molecules, such as aminoglycoside and myeloma light chains. These filtered molecules are rapidly endocytosed by the PTs and lead to nephrotoxicity. Methods To investigate whether inhibition of PT uptake of filtered toxins can reduce toxicity, we evaluated the ability of Lrpap1 or receptor-associated protein (RAP) to prevent PT endocytosis. Munich Wistar Frömter rats were used since both glomerular filtration and PT uptake can be visualized and quantified. The injury model chosen was the well-established gentamicin-induced toxicity, which leads to significant reductions in GFR and serum creatinine increases. CKD was induced with a right uninephrectomy and left 40-minute pedicle clamp. Rats had 8 weeks to recover and to stabilize GFR and proteinuria. Multiphoton microscopy was used to evaluate endocytosis in vivo and serum creatinine, and 24-hour creatinine clearances were used to evaluate kidney functional changes. Results Studies showed that preadministration of RAP significantly inhibited both albumin and dextran endocytosis in outer cortical PTs. Importantly, this inhibition was found to be rapidly reversible with time. RAP was also found to be an excellent inhibitor of PT gentamicin endocytosis. Finally, gentamicin administration for 6 days resulted in significant elevation of serum creatinine in vehicle-treated rats, but not in those receiving daily infusion of RAP before gentamicin. Conclusions This study provides a model for the potential use of RAP to prevent, in a reversible manner, PT endocytosis of potential nephrotoxins, thus protecting the kidney from damage.
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Affiliation(s)
- Mark C Wagner
- Indiana Center for Biological Microscopy, Indiana University School of Medicine, Indianapolis, Indiana
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4
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Soeorg H, Padari H, Kipper K, Ilmoja ML, Lutsar I, Metsvaht T. Pharmacokinetics of Gentamicin Components C1, C1a, and C2/C2a/C2b and Subsequent Decline in Glomerular Filtration Rate in Neonates. AAPS J 2022; 24:77. [DOI: 10.1208/s12248-022-00727-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/13/2022] [Indexed: 11/30/2022] Open
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5
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McHugh DR, Cotton CU, Hodges CA. Synergy between Readthrough and Nonsense Mediated Decay Inhibition in a Murine Model of Cystic Fibrosis Nonsense Mutations. Int J Mol Sci 2020; 22:ijms22010344. [PMID: 33396210 PMCID: PMC7794695 DOI: 10.3390/ijms22010344] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 12/15/2022] Open
Abstract
Many heritable genetic disorders arise from nonsense mutations, which generate premature termination codons (PTCs) in transcribed mRNA. PTCs ablate protein synthesis by prematurely terminating the translation of mutant mRNA, as well as reducing mutant mRNA quantity through targeted degradation by nonsense-mediated decay (NMD) mechanisms. Therapeutic strategies for nonsense mutations include facilitating ribosomal readthrough of the PTC and/or inhibiting NMD to restore protein function. However, the efficacy of combining readthrough agents and NMD inhibitors has not been thoroughly explored. In this study, we examined combinations of known NMD inhibitors and readthrough agents using functional analysis of the CFTR protein in primary cells from a mouse model carrying a G542X nonsense mutation in Cftr. We observed synergy between an inhibitor of the NMD component SMG-1 (SMG1i) and the readthrough agents G418, gentamicin, and paromomycin, but did not observe synergy with readthrough caused by amikacin, tobramycin, PTC124, escin, or amlexanox. These results indicate that treatment with NMD inhibitors can increase the quantity of functional protein following readthrough, and that combining NMD inhibitors and readthrough agents represents a potential therapeutic option for treating nonsense mutations.
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Affiliation(s)
- Daniel R. McHugh
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
| | - Calvin U. Cotton
- Department of Pediatrics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
| | - Craig A. Hodges
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
- Department of Pediatrics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
- Correspondence:
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6
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Unraveling the Gentamicin Drug Product Complexity Reveals Variation in Microbiological Activities and Nephrotoxicity. Antimicrob Agents Chemother 2020; 64:AAC.00533-20. [PMID: 32601158 DOI: 10.1128/aac.00533-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
The gentamicin drug product is a complex mixture of numerous components, many of which have not individually undergone safety and efficacy assessments. This is in contrast to the majority of medicines that require rigorous characterizations of trace impurities and are dosed as single components. In gentamicin, four components, known as gentamicin congeners C1, C1a, C2, and C2a, comprise the majority of the mixture. A liquid chromatography-mass spectroscopy analysis revealed that the relative abundances of each gentamicin congener in commercial formulations can vary up to 1.9-fold depending on the commercial source of the gentamicin. To determine if the gentamicin used for antibiotic susceptibility testing (AST) would be predictive of the microbiological activity of the product used to dose patients, the relative abundances of the four congeners contained on commercial AST disks were measured. It was found that the congener abundances on the commercial AST disks varied up to 4.1-fold. After purification of the four gentamicin congeners, similar potencies against bacterial strains lacking aminoglycoside-modifying enzymes (AMEs) were observed. However, the potency of the congeners against strains harboring a common AME differed up to 128-fold. Nephrotoxicity of the individual gentamicin congeners also differed significantly in cell-based and repeat-dose rat nephrotoxicity studies. Variations in the composition of commercial gentamicin products combined with toxicity differences between gentamicin congeners suggest that some gentamicin formulations may be more nephrotoxic. Our results also raise the concern that gentamicin susceptibility test results may not be predictive of patient outcomes and could lead to unexpected clinical treatment failures.
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7
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Xie X, Zhu JW, Liu Y, Jiang H. Application of Genetic Engineering Approaches to Improve Bacterial Metabolite Production. Curr Protein Pept Sci 2020; 21:488-496. [DOI: 10.2174/1389203721666191223145827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/28/2019] [Accepted: 10/27/2019] [Indexed: 02/06/2023]
Abstract
Genetic engineering is a powerful method to improve the fermentation yield of bacterial
metabolites. Since many biosynthetic mechanisms of bacterial metabolites have been unveiled, genetic
engineering approaches have been applied to various issues of biosynthetic pathways, such as transcription,
translation, post-translational modification, enzymes, transporters, etc. In this article, natamycin,
avermectins, gentamicins, piperidamycins, and β-valienamine have been chosen as examples
to review recent progress in improving their production by genetic engineering approaches. In these
cases, not only yields of target products have been increased, but also yields of by-products have been
decreased, and new products have been created.
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Affiliation(s)
- Xin Xie
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jia-Wei Zhu
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yi Liu
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hui Jiang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
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8
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McHugh DR, Steele MS, Valerio DM, Miron A, Mann RJ, LePage DF, Conlon RA, Cotton CU, Drumm ML, Hodges CA. A G542X cystic fibrosis mouse model for examining nonsense mutation directed therapies. PLoS One 2018; 13:e0199573. [PMID: 29924856 PMCID: PMC6010256 DOI: 10.1371/journal.pone.0199573] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/08/2018] [Indexed: 12/22/2022] Open
Abstract
Nonsense mutations are present in 10% of patients with CF, produce a premature termination codon in CFTR mRNA causing early termination of translation, and lead to lack of CFTR function. There are no currently available animal models which contain a nonsense mutation in the endogenous Cftr locus that can be utilized to test nonsense mutation therapies. In this study, we create a CF mouse model carrying the G542X nonsense mutation in Cftr using CRISPR/Cas9 gene editing. The G542X mouse model has reduced Cftr mRNA levels, demonstrates absence of CFTR function, and displays characteristic manifestations of CF mice such as reduced growth and intestinal obstruction. Importantly, CFTR restoration is observed in G542X intestinal organoids treated with G418, an aminoglycoside with translational readthrough capabilities. The G542X mouse model provides an invaluable resource for the identification of potential therapies of CF nonsense mutations as well as the assessment of in vivo effectiveness of these potential therapies targeting nonsense mutations.
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Affiliation(s)
- Daniel R. McHugh
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Miarasa S. Steele
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Dana M. Valerio
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Alexander Miron
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Rachel J. Mann
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - David F. LePage
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ronald A. Conlon
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Calvin U. Cotton
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Mitchell L. Drumm
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Craig A. Hodges
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
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9
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Abstract
Aminoglycosides remain a vital clinical asset. Gentamicin C complex in particular is remarkably potent in treating systemic Gram-negative infections, and semisynthetic gentamicins that combat pathogen resistance or show reduced toxicity remain attractive goals. We report here the roles of clustered genes and enzymes that define a methylation network in gentamicin biosynthesis and also identify a remote gene on the chromosome encoding the essential methyltransferase GenL, which is decisive for the proportions of the five major components present in the gentamicin C complex. This is an important step toward engineered fermentation to produce single components as valuable starting materials for semisynthesis of next-generation aminoglycoside antibiotics. Gentamicin C complex from Micromonospora echinospora remains a globally important antibiotic, and there is revived interest in the semisynthesis of analogs that might show improved therapeutic properties. The complex consists of five components differing in their methylation pattern at one or more sites in the molecule. We show here, using specific gene deletion and chemical complementation, that the gentamicin pathway up to the branch point is defined by the selectivity of the methyltransferases GenN, GenD1, and GenK. Unexpectedly, they comprise a methylation network in which early intermediates are ectopically modified. Using whole-genome sequence, we have also discovered the terminal 6′-N-methyltransfer required to produce gentamicin C2b from C1a or gentamicin C1 from C2, an example of an essential biosynthetic enzyme being located not in the biosynthetic gene cluster but far removed on the chromosome. These findings fully account for the methylation pattern in gentamicins and open the way to production of individual gentamicins by fermentation, as starting materials for semisynthesis.
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10
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Richardson R, Smart M, Tracey-White D, Webster AR, Moosajee M. Mechanism and evidence of nonsense suppression therapy for genetic eye disorders. Exp Eye Res 2017; 155:24-37. [PMID: 28065590 DOI: 10.1016/j.exer.2017.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/24/2016] [Accepted: 01/04/2017] [Indexed: 01/09/2023]
Abstract
Between 5 and 70% of genetic disease is caused by in-frame nonsense mutations, which introduce a premature termination codon (PTC) within the disease-causing gene. Consequently, during translation, non-functional or gain-of-function truncated proteins of pathological significance, are formed. Approximately 50% of all inherited retinal disorders have been associated with PTCs, highlighting the importance of novel pharmacological or gene correction therapies in ocular disease. Pharmacological nonsense suppression of PTCs could delineate a therapeutic strategy that treats the mutation in a gene- and disease-independent manner. This approach aims to suppress the fidelity of the ribosome during protein synthesis so that a near-cognate aminoacyl-tRNA, which shares two of the three nucleotides of the PTC, can be inserted into the peptide chain, allowing translation to continue, and a full-length functional protein to be produced. Here we discuss the mechanisms and evidence of nonsense suppression agents, including the small molecule drug ataluren (or PTC124) and next generation 'designer' aminoglycosides, for the treatment of genetic eye disease.
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Affiliation(s)
- Rose Richardson
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK
| | - Matthew Smart
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK
| | - Dhani Tracey-White
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK
| | - Andrew R Webster
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Mariya Moosajee
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK.
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11
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Biosynthesis of 3″-demethyl-gentamicin C components by gen N disruption strain of Micromonospora echinospora and test their antimicrobial activities in vitro. Microbiol Res 2016; 185:36-44. [DOI: 10.1016/j.micres.2016.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 01/19/2016] [Accepted: 01/24/2016] [Indexed: 11/21/2022]
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12
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Gu Y, Ni X, Ren J, Gao H, Wang D, Xia H. Biosynthesis of Epimers C2 and C2a in the Gentamicin C Complex. Chembiochem 2015; 16:1933-1942. [DOI: 10.1002/cbic.201500258] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Indexed: 11/09/2022]
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13
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Huang C, Huang F, Moison E, Guo J, Jian X, Duan X, Deng Z, Leadlay PF, Sun Y. Delineating the biosynthesis of gentamicin x2, the common precursor of the gentamicin C antibiotic complex. ACTA ACUST UNITED AC 2015; 22:251-61. [PMID: 25641167 PMCID: PMC4340712 DOI: 10.1016/j.chembiol.2014.12.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/03/2014] [Accepted: 12/06/2014] [Indexed: 11/24/2022]
Abstract
Gentamicin C complex is a mixture of aminoglycoside antibiotics used worldwide to treat severe Gram-negative bacterial infections. Despite its clinical importance, the enzymology of its biosynthetic pathway has remained obscure. We report here insights into the four enzyme-catalyzed steps that lead from the first-formed pseudotrisaccharide gentamicin A2 to gentamicin X2, the last common intermediate for all components of the C complex. We have used both targeted mutations of individual genes and reconstitution of portions of the pathway in vitro to show that the secondary alcohol function at C-3″ of A2 is first converted to an amine, catalyzed by the tandem operation of oxidoreductase GenD2 and transaminase GenS2. The amine is then specifically methylated by the S-adenosyl-l-methionine (SAM)-dependent N-methyltransferase GenN to form gentamicin A. Finally, C-methylation at C-4″ to form gentamicin X2 is catalyzed by the radical SAM-dependent and cobalamin-dependent enzyme GenD1.
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Affiliation(s)
- Chuan Huang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People's Republic of China
| | - Fanglu Huang
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Eileen Moison
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Junhong Guo
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People's Republic of China
| | - Xinyun Jian
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People's Republic of China
| | - Xiaobo Duan
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People's Republic of China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People's Republic of China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, People's Republic of China
| | - Peter F Leadlay
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
| | - Yuhui Sun
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People's Republic of China.
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14
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Vallon V. Do tubular changes in the diabetic kidney affect the susceptibility to acute kidney injury? Nephron Clin Pract 2014; 127:133-8. [PMID: 25343837 DOI: 10.1159/000363554] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Diabetes is the single largest contributor to the growing prevalence of chronic kidney disease (CKD), and episodes of acute kidney injury (AKI) increase the risk of advanced CKD in diabetic patients. Here we discuss whether the pathophysiological changes that occur in the tubular system of the diabetic kidney affect the intrinsic susceptibility to AKI. There is abundant data showing that drug-induced nephrotoxicity is attenuated in rodents with experimental diabetes mellitus, and some mechanistic explanations have been provided, in particular in response to aminoglycosides. Besides downregulation in proximal tubular megalin, which mediates the aminoglycoside uptake in proximal tubules, a role for hyperglycemia-induced activation of regenerative mechanisms has been proposed. The available clinical data, however, indicates that diabetes is a risk factor for AKI, including aminoglycoside nephrotoxicity. While much needs to be learned about this disconnect, the isolated induction of diabetes in otherwise healthy young adult rodents may simply not fully mimic the influence that diabetes exerts in the setting of a critically ill and often elderly patient. We speculate that diabetic tubular growth and the associated molecular signature (including upregulation of TGF-β, senescence, and inflammation) set up the development of diabetic nephropathy and renal failure in part by increasing the susceptibility to AKI, which further promotes hypoxia and apoptosis. Considering the strong association between AKI episodes and the cumulative risk of developing advanced CKD in diabetes, strategies that reduce AKI in these patients are expected to help reduce the growing burden of end-stage renal disease.
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Affiliation(s)
- Volker Vallon
- Division of Nephrology-Hypertension, Departments of Medicine and Pharmacology, University of California San Diego, and VA San Diego Healthcare System, San Diego, Calif., USA
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15
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Guo J, Huang F, Huang C, Duan X, Jian X, Leeper F, Deng Z, Leadlay PF, Sun Y. Specificity and promiscuity at the branch point in gentamicin biosynthesis. ACTA ACUST UNITED AC 2014; 21:608-18. [PMID: 24746560 PMCID: PMC4039129 DOI: 10.1016/j.chembiol.2014.03.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 11/30/2022]
Abstract
Gentamicin C complex is a mixture of aminoglycoside antibiotics used to treat severe Gram-negative bacterial infections. We report here key features of the late-stage biosynthesis of gentamicins. We show that the intermediate gentamicin X2, a known substrate for C-methylation at C-6' to form G418 catalyzed by the radical SAM-dependent enzyme GenK, may instead undergo oxidation at C-6' to form an aldehyde, catalyzed by the flavin-linked dehydrogenase GenQ. Surprisingly, GenQ acts in both branches of the pathway, likewise oxidizing G418 to an analogous ketone. Amination of these intermediates, catalyzed mainly by aminotransferase GenB1, produces the known intermediates JI-20A and JI-20B, respectively. Other pyridoxal phosphate-dependent enzymes (GenB3 and GenB4) act in enigmatic dehydroxylation steps that convert JI-20A and JI-20B into the gentamicin C complex or (GenB2) catalyze the epimerization of gentamicin C2a into gentamicin C2.
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Affiliation(s)
- Junhong Guo
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), and School of Pharmaceutical Sciences, Wuhan University, Wuhan, Wuchang 430071, People's Republic of China
| | - Fanglu Huang
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Chuan Huang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), and School of Pharmaceutical Sciences, Wuhan University, Wuhan, Wuchang 430071, People's Republic of China
| | - Xiaobo Duan
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), and School of Pharmaceutical Sciences, Wuhan University, Wuhan, Wuchang 430071, People's Republic of China
| | - Xinyun Jian
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), and School of Pharmaceutical Sciences, Wuhan University, Wuhan, Wuchang 430071, People's Republic of China
| | - Finian Leeper
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), and School of Pharmaceutical Sciences, Wuhan University, Wuhan, Wuchang 430071, People's Republic of China
| | - Peter F Leadlay
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
| | - Yuhui Sun
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), and School of Pharmaceutical Sciences, Wuhan University, Wuhan, Wuchang 430071, People's Republic of China.
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16
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Hall AM, Rhodes GJ, Sandoval RM, Corridon PR, Molitoris BA. In vivo multiphoton imaging of mitochondrial structure and function during acute kidney injury. Kidney Int 2013; 83:72-83. [PMID: 22992467 PMCID: PMC4136483 DOI: 10.1038/ki.2012.328] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mitochondrial dysfunction has been implicated in the pathogenesis of acute kidney injury due to ischemia and toxic drugs. Methods for imaging mitochondrial function in cells using confocal microscopy are well established; more recently, it was shown that these techniques can be utilized in ex vivo kidney tissue using multiphoton microscopy. We extended this approach in vivo and found that kidney mitochondrial structure and function can be imaged in anesthetized rodents using multiphoton excitation of endogenous and exogenous fluorophores. Mitochondrial nicotinamide adenine dinucleotide increased markedly in rat kidneys in response to ischemia. Following intravenous injection, the mitochondrial membrane potential-dependent dye TMRM was taken up by proximal tubules; in response to ischemia, the membrane potential dissipated rapidly and mitochondria became shortened and fragmented in proximal tubules. In contrast, the mitochondrial membrane potential and structure were better maintained in distal tubules. Changes in mitochondrial structure, nicotinamide adenine dinucleotide, and membrane potential were found in the proximal, but not distal, tubules after gentamicin exposure. These changes were sporadic, highly variable among animals, and were preceded by changes in non-mitochondrial structures. Thus, real-time changes in mitochondrial structure and function can be imaged in rodent kidneys in vivo using multiphoton excitation of endogenous and exogenous fluorophores in response to ischemia-reperfusion injury or drug toxicity.
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MESH Headings
- Acute Kidney Injury/etiology
- Acute Kidney Injury/pathology
- Acute Kidney Injury/physiopathology
- Animals
- Gentamicins/adverse effects
- Glutathione/metabolism
- Ischemia/complications
- Kidney/blood supply
- Kidney Tubules, Distal/metabolism
- Kidney Tubules, Distal/pathology
- Kidney Tubules, Distal/physiopathology
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Kidney Tubules, Proximal/physiopathology
- Male
- Membrane Potential, Mitochondrial/physiology
- Mice
- Mice, Inbred C57BL
- Microscopy, Fluorescence, Multiphoton/methods
- Mitochondria/pathology
- Mitochondria/physiology
- NAD/metabolism
- Rats
- Rats, Sprague-Dawley
- Rats, Wistar
- Reactive Oxygen Species/metabolism
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Affiliation(s)
- Andrew M Hall
- University College London Centre for Nephrology, Royal Free Hospital, London, UK.
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17
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Keeling KM, Bedwell DM. Suppression of nonsense mutations as a therapeutic approach to treat genetic diseases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:837-52. [PMID: 21976286 DOI: 10.1002/wrna.95] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Suppression therapy is a treatment strategy for genetic diseases caused by nonsense mutations. This therapeutic approach utilizes pharmacological agents that suppress translation termination at in-frame premature termination codons (PTCs) to restore translation of a full-length, functional polypeptide. The efficiency of various classes of compounds to suppress PTCs in mammalian cells is discussed along with the current limitations of this therapy. We also elaborate on approaches to improve the efficiency of suppression that include methods to enhance the effectiveness of current suppression drugs and the design or discovery of new, more effective suppression agents. Finally, we discuss the role of nonsense-mediated mRNA decay (NMD) in limiting the effectiveness of suppression therapy, and describe tactics that may allow the efficiency of NMD to be modulated in order to enhance suppression therapy.
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Affiliation(s)
- Kim M Keeling
- Department of Microbiology, Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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18
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Kandasamy J, Atia-Glikin D, Belakhov V, Baasov T. Repairing faulty genes by aminoglycosides: Identification of new pharmacophore with enhanced suppression of disease-causing nonsense mutations. MEDCHEMCOMM 2011. [DOI: 10.1039/c0md00195c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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19
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Statins inhibit aminoglycoside accumulation and cytotoxicity to renal proximal tubule cells. Biochem Pharmacol 2010; 79:647-54. [DOI: 10.1016/j.bcp.2009.09.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 09/16/2009] [Accepted: 09/17/2009] [Indexed: 11/23/2022]
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20
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Chittapragada M, Roberts S, Ham YW. Aminoglycosides: molecular insights on the recognition of RNA and aminoglycoside mimics. PERSPECTIVES IN MEDICINAL CHEMISTRY 2009; 3:21-37. [PMID: 19812740 PMCID: PMC2754922 DOI: 10.4137/pmc.s2381] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
RNA is increasingly recognized for its significant functions in biological systems and has recently become an important molecular target for therapeutics development. Aminoglycosides, a large class of clinically significant antibiotics, exert their biological functions by binding to prokaryotic ribosomal RNA (rRNA) and interfering with protein translation, resulting in bacterial cell death. They are also known to bind to viral mRNAs such as HIV-1 RRE and TAR. Consequently, aminoglycosides are accepted as the single most important model in understanding the principles that govern small molecule-RNA recognition, which is essential for the development of novel antibacterial, antiviral or even anti-oncogenic agents. This review outlines the chemical structures and mechanisms of molecular recognition and antibacterial activity of aminoglycosides and various aminoglycoside mimics that have recently been devised to improve biological efficacy, binding affinity and selectivity, or to circumvent bacterial resistance.
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Affiliation(s)
- Maruthi Chittapragada
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, U.S.A
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21
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Hanessian S, Szychowski J, Maianti JP. Synthesis and Comparative Antibacterial Activity of Verdamicin C2 and C2a. A New Oxidation of Primary Allylic Azides in Dihydro[2H]pyrans. Org Lett 2008; 11:429-32. [DOI: 10.1021/ol802421d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen Hanessian
- Department of Chemistry, Université de Montréal, C. P. 6128, Succ. Centre-Ville, Montréal, P.Q., Canada, H3C 3J7
| | - Janek Szychowski
- Department of Chemistry, Université de Montréal, C. P. 6128, Succ. Centre-Ville, Montréal, P.Q., Canada, H3C 3J7
| | - J. Pablo Maianti
- Department of Chemistry, Université de Montréal, C. P. 6128, Succ. Centre-Ville, Montréal, P.Q., Canada, H3C 3J7
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22
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Azimov R, Abuladze N, Sassani P, Newman D, Kao L, Liu W, Orozco N, Ruchala P, Pushkin A, Kurtz I. G418-mediated ribosomal read-through of a nonsense mutation causing autosomal recessive proximal renal tubular acidosis. Am J Physiol Renal Physiol 2008; 295:F633-41. [PMID: 18614622 DOI: 10.1152/ajprenal.00015.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Autosomal recessive proximal renal tubular acidosis is caused by mutations in the SLC4A4 gene encoding the electrogenic sodium bicarbonate cotransporter NBCe1-A. The mutations that have been characterized thus far result in premature truncation, mistargeting, or decreased function of the cotransporter. Despite bicarbonate treatment to correct the metabolic acidosis, extrarenal manifestations persist, including glaucoma, cataracts, corneal opacification, and mental retardation. Currently, there are no known therapeutic approaches that can specifically target mutant NBCe1-A proteins. In the present study, we tested the hypothesis that the NBCe1-A-Q29X mutation can be rescued in vitro by treatment with aminoglycoside antibiotics, which are known for their ability to suppress premature stop codons. As a model system, we cloned the NBCe1-A-Q29X mutant into a vector lacking an aminoglycoside resistance gene and transfected the mutant cotransporter in HEK293-H cells. Cells transfected with the NBCe1-A-Q29X mutant failed to express the cotransporter because of the premature stop codon. Treatment of the cells with G418 significantly increased the expression of the full-length cotransporter, as assessed by immunoblot analysis. Furthermore, immunocytochemical studies demonstrated that G418 treatment induced cotransporter expression on the plasma membrane whereas in the absence of G418, NBCe1-A-Q29X was not expressed. In HEK293-H cells transfected with the NBCe1-A-Q29X mutant not treated with G418, NBCe1-A-mediated flux was not detectable. In contrast, in cells transfected with the NBCe1-A-Q29X mutant, G418 treatment induced Na(+)- and HCO(3)(-)-dependent transport that did not differ from wild-type NBCe1-A function. G418 treatment in mock-transfected cells was without effect. In conclusion, G418 induces ribosomal read-through of the NBCe1-A-Q29X mutation in HEK293-H cells. These findings represent the first evidence that in the presence of the NBCe1-A-Q29X mutation that causes proximal renal tubular acidosis, full-length functional NBCe1-A protein can be produced. Our results provide the first demonstration of a mutation in NBCe1-A that has been treated in a targeted and specific manner.
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Affiliation(s)
- Rustam Azimov
- Division of Nephrology, David Geffen School of Medicine at UCLA, University of California-Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
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23
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Calcium-sensing receptor antagonism or lithium treatment ameliorates aminoglycoside-induced cell death in renal epithelial cells. Biochim Biophys Acta Mol Basis Dis 2008; 1782:188-95. [PMID: 18261471 DOI: 10.1016/j.bbadis.2008.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 01/07/2008] [Accepted: 01/08/2008] [Indexed: 11/21/2022]
Abstract
The aminoglycoside antibiotic gentamicin elicits proximal tubular toxicity and cell death. In calcium-sensing receptor (CaR)-transfected HEK-293 (CaR-HEK) cells and CaR-expressing proximal tubule-derived opossum kidney (OK) cells, chronic gentamicin treatment elicits dose-dependent, caspase-mediated apoptotic cell death. Here we investigated whether the renal cell toxicity of the CaR agonist gentamicin could be prevented by CaR antagonism or by lithium cotreatment which may interfere with receptor-mediated signalling. Chronic treatment of OK and CaR-HEK cells with low concentrations of gentamicin elicited cell death, an effect that was ameliorated by cotreatment with the CaR negative allosteric modulator (calcilytic) NPS-89636. This calcilytic also attenuated CaR agonist-induced ERK activation in these cells. In addition, 1 mM LiCl, equivalent to its therapeutic plasma concentration, also inhibited gentamicin-induced toxicity in both cell types. This protective effect of lithium was not due to the disruption of phosphatidylinositol-mediated gentamicin uptake as the cellular entry of Texas red-conjugated gentamicin into OK and CaR-HEK cells was unchanged by lithium treatment. However, the protective effect of lithium was mimicked by glycogen synthase 3beta inhibition. Together, these data implicate CaR activation and a lithium-inhibitable signalling pathway in the induction of cell death by gentamicin in renal epithelial cells in culture.
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24
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Sandoval RM, Molitoris BA. Quantifying endocytosis in vivo using intravital two-photon microscopy. Methods Mol Biol 2008; 440:389-402. [PMID: 18369960 DOI: 10.1007/978-1-59745-178-9_28] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The recent introduction of multiphoton microscopy coupled with advances in optics, computer sciences, designer fluorophores, molecular labeling, and previously developed physiologic approaches have empowered investigators to quantitatively study the cell-specific dynamic events, such as endocytosis, within a functioning organ with subcellular resolution. This rapidly emerging field of investigation, with superior spatial and temporal resolution and high sensitivity, enables investigators to track molecules and determine their mode of cellular uptake, intracellular trafficking, and metabolism in a cell-specific fashion in complex heterogeneous organs such as the kidney with repeated determinations possible over a prolonged period of time. This approach is enhanced by the ability to obtain and quantify volumetric data with using up to three different fluorophores simultaneously. We have utilized this intravital approach to understand and quantify kidney proximal tubule cell uptake and intracellular distribution and metabolism of fluorescently labeled molecules, including folic acid, gentamicin, and small interfering ribonucleic acid (siRNA). Limitations of this technique include tissue penetration, which is the major barrier to successful clinical utilization of this technology. However, its use in preclinical animal models offers new insight into physiologic processes and the pathophysiology and treatment of disease processes.
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Affiliation(s)
- Ruben M Sandoval
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
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25
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Hainrichson M, Nudelman I, Baasov T. Designer aminoglycosides: the race to develop improved antibiotics and compounds for the treatment of human genetic diseases. Org Biomol Chem 2007; 6:227-39. [PMID: 18174989 DOI: 10.1039/b712690p] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aminoglycosides are highly potent, broad-spectrum antibiotics that exert their bactericidal therapeutic effect by selectively binding to the decoding aminoacyl site (A-site) of the bacterial 16 S rRNA, thereby interfering with translational fidelity during protein synthesis. The appearance of bacterial strains resistant to these drugs, as well as their relative toxicity, have inspired extensive searches towards the goal of obtaining novel molecular designs with improved antibacterial activity and reduced toxicity. In the last few years, a new, aminoglycoside dependent therapeutic approach for the treatment of certain human genetic diseases has been identified. These treatments rely on the ability of certain aminoglycosides to induce mammalian ribosomes to readthrough premature stop codon mutations. This new and challenging task has introduced fresh research avenues in the field of aminoglycoside research. Recent observations and current challenges in the design of aminoglycosides with improved antibacterial activity and the treatment of human genetic diseases are discussed.
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Affiliation(s)
- Mariana Hainrichson
- The Edith and Joseph Fischer Enzyme Inhibitors Laboratory, Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
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26
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Abstract
Prevention of ototoxicity after the administration of aminoglycoside antibiotics has been notably difficult, in particular in patients with chronic kidney disease. Feldman et al. report that oral administration of 600 mg N-acetylcysteine twice daily significantly ameliorates gentamicin-induced ototoxicity in hemodialysis patients. That approach may help to prevent aminoglycoside-induced hearing loss in these high-risk patients in daily practice.
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Affiliation(s)
- M Tepel
- Charité Campus Benjamin Franklin, Medizinische Klinik IV, Nephrologie, Berlin, Germany.
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27
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Bolisetty S, Agarwal A. Subclinical kidney injury incites endotoxin hyperresponsiveness. Am J Physiol Renal Physiol 2007; 293:F41-2. [PMID: 17507600 DOI: 10.1152/ajprenal.00224.2007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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