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Hadipour Moghaddam SP, Mohammadpour R, Ghandehari H. RETRACTED: In vitro and in vivo evaluation of degradation, toxicity, biodistribution, and clearance of silica nanoparticles as a function of size, porosity, density, and composition. J Control Release 2019; 311-312:1-15. [PMID: 31465825 PMCID: PMC6874921 DOI: 10.1016/j.jconrel.2019.08.028] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 08/23/2019] [Accepted: 08/25/2019] [Indexed: 12/19/2022]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the corresponding author. Subsequent to the publication of the article Journal of Controlled Release 311–312 (2019) 1–15, in follow up studies in 2021, the corresponding author's lab members noticed significant discrepancies in reproducibility of some of the results reported in this manuscript. A detailed investigation in the lab was launched, and by retrieving the raw data available at the core facility pertaining to this manuscript, the following discrepancies were discovered that provide the basis for this retraction. These discrepancies have been reported to the University of Utah Research Integrity and Compliance Office by the corresponding author. The co-authors have been made aware of these discrepancies and of the decision of the corresponding author to retract. The corresponding author believes that the subject matter of this article, detailed analysis of the degradation of silica nanoparticles as a function of their physicochemical properties in relevant biological media in vitro, and in vivo, is significant. For successful utility of these particles in drug delivery applications their detailed biological fate needs to be examined. The significant discrepancies and lack of reproducibility of the reported data however is very unfortunate and the author hopes that this does not cast a doubt on the need for more detailed examination of the biological fate of silica nanoparticles in the future for their successful application in controlled release. In Vitro Data (Fig. 3) • Actual dissolution reaction volume was 2.5mL (confirmed by reviewing the lab notebook of the first author during the investigation) vs 3.5mL reported in the manuscript. • Sample volume was not used in the calculation to convert Inductively Coupled Plasma Mass Spectrometry (ICPMS) data to mg of silicon retrieved which is needed to calculate % degradation (needed to multiply data by 0.1 due to 0.1mL sample volumes). • Our investigation revealed a 20% “matrix effect with fluids” was communicated by ICPMS core facility person to the first author that was not addressed in the manuscript. • All data is different when calculating % degradation, not just by a factor of 10 due to not calculating for the 100ml sample volume. • Raw data during our investigation after publication, obtained from ICPMS facility, and not noted in the lab notebook, for day 28 of simulated lysosomal fluid (SLF) reveals n=1 and no data points for Stober100. In the manuscript however, error bars are shown for all particles at this time point and for the data for Stober100. Intracellular Degradation (Fig. 5) • Extremely high background with control causing negative % degradation for Disulfide Meso 100 from retrieved ICPMS data from core facility after publication, but manuscript shows ~1.25% degradation. • All other calculated % degradation based on retrieved data from ICPMS facility during the investigation after publication, do not match reported data in the paper. • Paper claims n=6, but raw data received from ICPMS facility during investigation (after publication) is clearly n=3. In Vivo Degradation (Fig. 6) ICPMS data retrieved during the investigation after publication for control mice showed extremely high background, and probably were not used in the calculations reported in this manuscript because it would have led to negative silicon contents for a few samples. Urine ICPMS data from the core facility was not available during investigation after publication, and cannot be retrieved from the first author's lab notebook. Hence its validity cannot be ascertained. There may be other discrepancies in the manuscript that have gone unnoticed. However, the Editor-in-Chief agrees that the above is significant enough to warrant retraction of the manuscript.
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Affiliation(s)
- Seyyed Pouya Hadipour Moghaddam
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA; Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA
| | - Raziye Mohammadpour
- Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA
| | - Hamidreza Ghandehari
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA; Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA; Department of Bioemedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
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Mechanism of proton/substrate coupling in the heptahelical lysosomal transporter cystinosin. Proc Natl Acad Sci U S A 2012; 109:E210-7. [PMID: 22232659 DOI: 10.1073/pnas.1115581109] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Secondary active transporters use electrochemical gradients provided by primary ion pumps to translocate metabolites or drugs "uphill" across membranes. Here we report the ion-coupling mechanism of cystinosin, an unusual eukaryotic, proton-driven transporter distantly related to the proton pump bacteriorhodopsin. In humans, cystinosin exports the proteolysis-derived dimeric amino acid cystine from lysosomes and is impaired in cystinosis. Using voltage-dependence analysis of steady-state and transient currents elicited by cystine and neutralization-scanning mutagenesis of conserved protonatable residues, we show that cystine binding is coupled to protonation of a clinically relevant aspartate buried in the membrane. Deuterium isotope substitution experiments are consistent with an access of this aspartate from the lysosomal lumen through a deep proton channel. This aspartate lies in one of the two PQ-loop motifs shared by cystinosin with a set of eukaryotic membrane proteins of unknown function and is conserved in about half of them, thus suggesting that other PQ-loop proteins may translocate protons.
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Nevo N, Chol M, Bailleux A, Kalatzis V, Morisset L, Devuyst O, Gubler MC, Antignac C. Renal phenotype of the cystinosis mouse model is dependent upon genetic background. Nephrol Dial Transplant 2009; 25:1059-66. [DOI: 10.1093/ndt/gfp553] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ruivo R, Anne C, Sagné C, Gasnier B. Molecular and cellular basis of lysosomal transmembrane protein dysfunction. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:636-49. [DOI: 10.1016/j.bbamcr.2008.12.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 12/10/2008] [Accepted: 12/11/2008] [Indexed: 02/04/2023]
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Kalatzis V, Antignac C. New aspects of the pathogenesis of cystinosis. Pediatr Nephrol 2003; 18:207-15. [PMID: 12644911 DOI: 10.1007/s00467-003-1077-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2002] [Revised: 11/04/2002] [Accepted: 11/08/2002] [Indexed: 10/25/2022]
Abstract
Cystinosis is a lysosomal transport disorder characterized by an intra-lysosomal accumulation of cystine, the disulfide of the amino acid cysteine. It is the most common inherited cause of the renal Fanconi syndrome. There are various clinical forms, infantile, juvenile, and ocular, based on age of onset and severity of symptoms. The first clinical description appeared in the early 1900s, but it was not until 1998 that the causative gene, CTNS, was identified. CTNS encodes cystinosin, a novel seven transmembrane domain (TM) protein. Cystinosin is a lysosomal membrane protein that requires two lysosomal targeting signals: a classic GYDQL motif in its C-terminal tail and a novel conformational motif, the core of which is YFPQA, situated in the fifth inter-TM loop. Cystinosin is the lysosomal cystine transporter and its activity is H(+)-driven. A mouse model of cystinosis was recently generated and Ctns(-/-) mice accumulate cystine in all tissues. A high level of cystine accumulates in the kidney, but these mice do not present with proximal tubulopathy or renal dysfunction. The Ctns(-/-) mouse model may provide clues to the cause of the Fanconi syndrome associated with cystinosis, the origin of which remains poorly understood.
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Cherqui S, Sevin C, Hamard G, Kalatzis V, Sich M, Pequignot MO, Gogat K, Abitbol M, Broyer M, Gubler MC, Antignac C. Intralysosomal cystine accumulation in mice lacking cystinosin, the protein defective in cystinosis. Mol Cell Biol 2002; 22:7622-32. [PMID: 12370309 PMCID: PMC135682 DOI: 10.1128/mcb.22.21.7622-7632.2002] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cystinosis is an autosomal recessive disorder characterized by an accumulation of intralysosomal cystine. The causative gene, CTNS, encodes cystinosin, a seven-transmembrane-domain protein, which we recently showed to be a lysosomal cystine transporter. The most severe and frequent form of cystinosis, the infantile form, appears around 6 to 12 months, with a proximal tubulopathy (de Toni-Debré-Fanconi syndrome) and ocular damage. End-stage renal failure is reached by 10 years of age. Accumulation of cystine in all tissues eventually leads to multisystemic disease. Treatment with cysteamine, which reduces the concentration of intracellular cystine, delays disease progression but has undesirable side effects. We report the first Ctns knockout mouse model generated using a promoter trap approach. We replaced the last four Ctns exons by an internal ribosome entry site-betagal-neo cassette and showed that the truncated protein was mislocalized and nonfunctional. Ctns(-/-) mice accumulated cystine in all organs tested, and cystine crystals, pathognomonic of cystinosis, were observed. Ctns(-/-) mice developed ocular changes similar to those observed in affected individuals, bone defects and behavioral anomalies. Interestingly, Ctns(-/-) mice did not develop signs of a proximal tubulopathy, or renal failure. A preliminary therapeutic trial using an oral administration of cysteamine was carried out and demonstrated the efficiency of this treatment for cystine clearance in Ctns(-/-) mice. This animal model will prove an invaluable and unique tool for testing emerging therapeutics for cystinosis.
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Abstract
In the group of lysosomal storage diseases, transport disorders occupy a special place because they represent rare examples of inborn errors of metabolism caused by a defect of an intracellular membrane transporter. In particular, two disorders are caused by a proven defect in carrier-mediated transport of metabolites: cystinosis and the group of sialic acid storage disorders (SASD). The recent identification of the gene mutations for both disorders will improve patient diagnosis and shed light on new physiological mechanisms of intracellular trafficking.
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Affiliation(s)
- G M Mancini
- Department of Clinical Genetics, Erasmus University, Rotterdam, The Netherlands.
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Moellering D, Mc Andrew J, Patel RP, Forman HJ, Mulcahy RT, Jo H, Darley-Usmar VM. The induction of GSH synthesis by nanomolar concentrations of NO in endothelial cells: a role for gamma-glutamylcysteine synthetase and gamma-glutamyl transpeptidase. FEBS Lett 1999; 448:292-6. [PMID: 10218495 DOI: 10.1016/s0014-5793(99)00371-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nitric oxide protects cells from oxidative stress through a number of direct scavenging reactions with free radicals but the effects of nitric oxide on the regulation of antioxidant enzymes are only now emerging. Using bovine aortic endothelial cells as a model, we show that nitric oxide, at physiological rates of production (1-3 nM/s), is capable of inducing the synthesis of glutathione through a mechanism involving gamma-glutamylcysteine synthetase and gamma-glutamyl transpeptidase. This novel nitric oxide signalling pathway is cGMP-independent and we hypothesize that it makes an important contribution to the anti-atherosclerotic and antioxidant properties of nitric oxide.
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Affiliation(s)
- D Moellering
- Department of Pathology, University of Alabama at Birmingham, 35294-0019, USA
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Potterf SB, Muller J, Bernardini I, Tietze F, Kobayashi T, Hearing VJ, Gahl WA. Characterization of a melanosomal transport system in murine melanocytes mediating entry of the melanogenic substrate tyrosine. J Biol Chem 1996; 271:4002-8. [PMID: 8626732 DOI: 10.1074/jbc.271.8.4002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In this study, we identify a transport system for tyrosine, the initial precursor of melanin synthesis, in the melanosomes of murine melanocytes. Melanosomes preloaded with tyrosine demonstrated countertransport of 10 microM [3H]tyrosine, indicating carrier-mediated transport. Melanosomal tyrosine transport was saturable, with an apparent Km for tyrosine transport of 54 microM and a maximal velocity of 15 pmol of tyrosine/unit of hexosaminidase/min. Transport was temperature-dependent (Ea = 7.5 kcal/mol) and showed stereospecificity for the l-isomer of tyrosine. Aromatic, neutral hydrophobic compounds (such as tryptophan and phenylalanine), as well as the small, bulky neutral amino acids (such as leucine, isoleucine, and methionine) competed for tyrosine transport. Tyrosine transport was inhibited by the classical system L analogue, 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid and by monoiodotyrosine, but not by cystine, lysine, glutamic acid, or 2-(methylamino)-isobutyric acid. Tyrosine transport showed no dependence on Na+ or K+, and did not require an acidic environment or the availability of free thiols. These results demonstrate the existence of a neutral amino acid carrier in murine melanocyte melanosomes which resembles the rat thyroid FRTL-5 lysosomal system h. This transport system is critical to the function of the melanosome since tyrosine is the essential substrate required for the synthesis of the pigment melanin.
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Affiliation(s)
- S B Potterf
- Laboratory of Cell Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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Chou HF, Vadgama J, Jonas AJ. Lysosomal transport of small molecules. BIOCHEMICAL MEDICINE AND METABOLIC BIOLOGY 1992; 48:179-93. [PMID: 1476786 DOI: 10.1016/0885-4505(92)90064-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- H F Chou
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance 90502
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Barrueco J, O'Leary D, Sirotnak F. Facilitated transport of methotrexate polyglutamates into lysosomes derived from S180 cells. Further characterization and evidence for a simple mobile carrier system with broad specificity for homo- or heteropeptides bearing a C-terminal glutamyl moiety. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)88654-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Pisoni RL, Thoene JG. The transport systems of mammalian lysosomes. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1071:351-73. [PMID: 1751541 DOI: 10.1016/0304-4157(91)90002-e] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- R L Pisoni
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor 48109-2029
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Pintos-Morell G, Jean G, Dechaux M, Niaudet P. Increased monocyte-dependent suppression of polyclonal activation of B lymphocytes from cystinotic children. Pediatr Nephrol 1991; 5:597-602. [PMID: 1911146 DOI: 10.1007/bf00856649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In infantile cystinosis the amino acid cystine preferentially accumulates in phagocytic cells, polymorphonuclear leucocytes (PMN) and monocytes, rather than in lymphocytes. We previously described functional abnormalities in the oxidative metabolism and locomotion of cystinotic PMN and monocytes. The present study shows an abnormal lymphocyte polyclonal activation as evidenced by a decreased immunoglobulin (Ig) production and generation of Ig-containing cells (ICC) in cultures of peripheral blood mononuclear cells (PBMC) from cystinotic children upon stimulation with pokeweed mitogen and Staphylococcus aureus Cowan I. However, monocyte depletion from cystinotic PBMC fully reconstituted Ig production and ICC generation, indicating: (1) the presence of an increased monocyte-dependent suppression on lymphocyte polyclonal activation, and (2) that the intrinsic ability of cystinotic lymphocytes to respond to polyclonal stimulation was preserved. The increased cystinotic monocyte-dependent suppressive effect was not mediated by prostaglandin E2 (PGE2) since its production by cystinotic PBMC upon polyclonal activation was not different from that of controls. In addition, the sensitivity of cystinotic lymphocytes to the immunosuppressive effect of varying concentrations of exogenous PGE2 was similar to that of controls. Finally, indomethacin and 2-mercaptoethanol, two agents able to scavenge hydroxyl (.OH) radicals, restored Ig production by cystinotic PBMC, suggesting a role for reactive oxygen species in the increased cystinotic monocyte-dependent suppression.
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Affiliation(s)
- G Pintos-Morell
- Department of Paediatrics, Hospital Germans Trías i Pujol, Badalona, Spain
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Barrueco J, Sirotnak F. Evidence for the facilitated transport of methotrexate polyglutamates into lysosomes derived from S180 cells. Basic properties and specificity for polyglutamate chain length. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99018-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Vadgama JV, Chang K, Kopple JD, Idriss JM, Jonas AJ. Characteristics of taurine transport in rat liver lysosomes. J Cell Physiol 1991; 147:447-54. [PMID: 2066365 DOI: 10.1002/jcp.1041470310] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Taurine (2-aminoethanesulfonic acid) is a unique sulfur amino acid derivative that has putative nutritional, osmoregulatory, and neuroregulatory roles and is highly concentrated within a variety of cells. The permeability of Percoll density gradient purified rat liver lysosomes to taurine was examined. Intralysosomal amino acid analysis showed trace levels of taurine compared to most other amino acids. Taurine uptake was Na(+)-independent, with an overshoot between 5-10 minutes. Trichloroacetic acid extraction studies and detergent lysis confirmed that free taurine accumulated in the lysosomal space. Kinetic studies revealed heterogeneous uptake with values for Km1 = 31 +/- 1.82 and Km2 greater than 198 +/- 10.2 mM. The uptake had a pH optimal of 6.5 and was stimulated by the potassium specific ionophore valinomycin. The exodus rate was fairly rapid, with a t1/2 of 5 minutes at 37 degrees C. Analog inhibition studies indicated substrate specificity similar to the plasma membrane beta-alanine carrier system, with inhibition by beta-alanine, hypotaurine, and taurine. alpha-Alanine, 2-methylaminoisobutyric acid (MeAIB), and threonine were poor inhibitors. No effects were observed with sucrose and the photoaffinity derivative of taurine NAP-taurine [N-(4-azido-2-nitrophenyl)-2-aminoethanesulfonate]. In summary, rat liver lysosomes possess a high Km system for taurine transport that is sensitive to changes in K+ gradient and perhaps valinomycin induced diffusional membrane potential. These features may enable lysosomes to adapt to changing intracellular concentrations of this osmotic regulatory substance.
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Affiliation(s)
- J V Vadgama
- Division of Medical Genetics, Harbor-UCLA Medical Center, Torrance 90502
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