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Hsieh YYP, Sun W, Young JM, Cheung R, Hogan DA, Dandekar AA, Malik HS. Widespread fungal-bacterial competition for magnesium lowers bacterial susceptibility to polymyxin antibiotics. PLoS Biol 2024; 22:e3002694. [PMID: 38900845 PMCID: PMC11218974 DOI: 10.1371/journal.pbio.3002694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 07/02/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024] Open
Abstract
Fungi and bacteria coexist in many polymicrobial communities, yet the molecular basis of their interactions remains poorly understood. Here, we show that the fungus Candida albicans sequesters essential magnesium ions from the bacterium Pseudomonas aeruginosa. To counteract fungal Mg2+ sequestration, P. aeruginosa expresses the Mg2+ transporter MgtA when Mg2+ levels are low. Thus, loss of MgtA specifically impairs P. aeruginosa in co-culture with C. albicans, but fitness can be restored by supplementing Mg2+. Using a panel of fungi and bacteria, we show that Mg2+ sequestration is a general mechanism of fungal antagonism against gram-negative bacteria. Mg2+ limitation enhances bacterial resistance to polymyxin antibiotics like colistin, which target gram-negative bacterial membranes. Indeed, experimental evolution reveals that P. aeruginosa evolves C. albicans-dependent colistin resistance via non-canonical means; antifungal treatment renders resistant bacteria colistin-sensitive. Our work suggests that fungal-bacterial competition could profoundly impact polymicrobial infection treatment with antibiotics of last resort.
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Affiliation(s)
- Yu-Ying Phoebe Hsieh
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Wanting Sun
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Janet M. Young
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Robin Cheung
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Ajai A. Dandekar
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Harmit S. Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
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Sadr S, Tahermohammadi H, Kaveh S, Khanbabaee G, Tabatabaei SA, Choopani R, Rouzbahani AK, Fadavi N, Derikvandi S. Fractional Exhalation Nitric Oxide (FeNO) changes in cystic fibrosis patients induced by compound honey syrup: a pretest-posttest clinical trial. BMC Pulm Med 2023; 23:488. [PMID: 38053097 PMCID: PMC10696786 DOI: 10.1186/s12890-023-02787-9] [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: 03/24/2023] [Accepted: 11/25/2023] [Indexed: 12/07/2023] Open
Abstract
OBJECTIVE To evaluate the effect of Persian medicine Syrup 'compound honey syrup (CHS)' on fractional exhalation nitric oxide (FENO) changes in patients with cystic fibrosis (CF). STUDY DESIGN We conducted a before-after clinical trial on 70 CF patients. All patients received classical treatments for CF along with CHS (including honey, Ginger, cinnamon, saffron, cardamom and galangal), 5-10 cc (depending on the age and weight of patients) in 100 cc of warm boiled water twice a day, 30 min after meals. In this clinical trial, before and 12 weeks after the start of the CHS, FeNO test was evaluated. RESULTS From 70 patients were enrolled, 44 patients completed this 12-week course of treatment. At the end of the study, changes in FeNO was significantly different before and after treatment (P-value < 0.05). At the end of the study, no dangerous side effects of CHS was reported. CONCLUSIONS This study revealed that CHS can be effective as a complementary and safe drug in the medication of CF patients.
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Affiliation(s)
- Saeed Sadr
- Department of Pediatric Pulmonology, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hanieh Tahermohammadi
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Persian Medicine Network (PMN), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Shahpar Kaveh
- Department of Traditional Medicine, School of Traditional Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Ghamartaj Khanbabaee
- Department of Pediatric Pulmonology, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Ahmad Tabatabaei
- Department of Pediatric Pulmonology, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasool Choopani
- Department of Traditional Medicine, School of Traditional Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Nafise Fadavi
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shima Derikvandi
- Faculty of Veterinary Medicine, Student University of Tehran, Tehran, Iran
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Jahdauti L, Muggeo A, Paturel V, Jaisson S, Luczka E, Coraux C, Guillard T. [Involvement of inorganic phosphate starvation in Pseudomonas aeruginosa bacterial virulence]. Rev Mal Respir 2023; 40:243-246. [PMID: 36828680 DOI: 10.1016/j.rmr.2023.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 02/24/2023]
Abstract
Pseudomonas aeruginosa is a bacterium causing a wide spectrum of nosocomial and opportunistic respiratory infections. As an element essential for bacterial metabolism , phosphorus is incorporated as an inorganic phosphate and regulated by a two-component PhoB-PhoR system. Recently, it has been shown that as a result of overexpression of virulence factors, including the PhoB transcription factor, P. aeruginosa exhibited increased virulence in phosphate-deficient conditions. Exploration of the relationship between phosphate homeostasis and P. aeruginosa virulence could effectively contribute to the development of new, simple and innovative therapeutic strategies.
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Affiliation(s)
- L Jahdauti
- Université de Reims Champagne-Ardenne, Inserm UMR-S 1250, P3Cell, Reims, France.
| | - A Muggeo
- Université de Reims Champagne-Ardenne, Inserm UMR-S 1250, P3Cell, Reims, France
| | - V Paturel
- Université de Reims Champagne-Ardenne, Inserm UMR-S 1250, P3Cell, Reims, France
| | - S Jaisson
- Laboratoire de biochimie, CHU de Reims, Reims, France
| | - E Luczka
- Université de Reims Champagne-Ardenne, Inserm UMR-S 1250, P3Cell, Reims, France
| | - C Coraux
- Université de Reims Champagne-Ardenne, Inserm UMR-S 1250, P3Cell, Reims, France
| | - T Guillard
- Université de Reims Champagne-Ardenne, Inserm UMR-S 1250, P3Cell, Reims, France
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Sankararaman S, Hendrix SJ, Schindler T. Update on the management of vitamins and minerals in cystic fibrosis. Nutr Clin Pract 2022; 37:1074-1087. [PMID: 35997322 PMCID: PMC9544449 DOI: 10.1002/ncp.10899] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/27/2022] [Accepted: 07/16/2022] [Indexed: 11/10/2022] Open
Abstract
Advancements in respiratory and nutrition management have significantly improved the survival of patients with cystic fibrosis (CF). With the availability of several nutrition interventions such as oral/enteral nutrition supplements, enteric‐coated pancreatic enzymes, and water‐miscible CF‐specific vitamin supplements, frank vitamin deficiencies—with the exception of vitamin D—are rarely encountered in current clinical practice. Whereas they were previously considered as micronutrients, our current understanding of fat‐soluble vitamins and minerals as antioxidants, immunomodulators, and disease biomarkers has been evolving. The impact of highly effective modulators on the micronutrient status of patients with CF remains elusive. This narrative review focuses on the updates on the management of fat‐soluble vitamins and other micronutrients in CF in the current era and identifies the gaps in our knowledge.
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Affiliation(s)
- Senthilkumar Sankararaman
- Department of Pediatrics, Division of Pediatric Gastroenterology, UH Rainbow Babies & Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Sara J Hendrix
- Department of Nutrition Services, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Terri Schindler
- Department of Pediatrics, Division of Pediatric Pulmonology, UH Rainbow Babies & Children's Hospital, Cleveland, Ohio, USA
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Mucoid Pseudomonas aeruginosa Can Produce Calcium-Gelled Biofilms Independent of the Matrix Components Psl and CdrA. J Bacteriol 2022; 204:e0056821. [PMID: 35416688 PMCID: PMC9112934 DOI: 10.1128/jb.00568-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Biofilms are aggregates of microorganisms embedded in an extracellular matrix comprised largely of exopolysaccharides (EPSs), nucleic acids, and proteins. Pseudomonas aeruginosa is an opportunistic human pathogen that is also a model organism for studying biofilms in the laboratory. Here, we define a novel program of biofilm development used by mucoid (alginate-overproducing) P. aeruginosa in the presence of elevated calcium. Calcium cations cross-link negatively charged alginate polymers, resulting in individual cells being suspended in an alginate gel. The formation of this type of structurally distinct biofilm is not reliant on the canonical biofilm EPS components Psl and Pel or the matrix protein CdrA. We also observed that mucoid P. aeruginosa biofilm cells do not have the typical elevated levels of the secondary messenger cyclic di-GMP (c-di-GMP), as expected of biofilm cells, nor does the overproduction of alginate rely on high c-di-GMP. This contrasts with nonmucoid biofilms in which the production of the matrix components Psl, Pel, and CdrA is positively regulated by elevated c-di-GMP. We further demonstrate that calcium-gelled alginate biofilms impede the penetration of the antibiotic tobramycin, thus protecting the biofilm community from antibiotic-mediated killing. Finally, we show that bacterial aggregates with a dispersed cell arrangement like laboratory-grown calcium-alginate biofilm structures are present in explanted cystic fibrosis (CF) lung samples. Our findings illustrate the diverse nature of biofilm formation and structure in P. aeruginosa. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa produces a complex biofilm matrix comprised of exopolysaccharides (EPSs), nucleic acids, and proteins. P. aeruginosa biofilm formation canonically depends on a variable combination of the exopolysaccharides Psl and Pel and the matrix protein CdrA. We demonstrate that mucoid P. aeruginosa, which overproduces the EPS alginate, possesses an entirely alternate and calcium-dependent method of biofilm formation. These mucoid biofilm structures do not require Psl, Pel, or CdrA, and they display a unique organization of individually suspended cells similar to bacterial aggregates observed in cystic fibrosis airways. Furthermore, calcium-gelled mucoid biofilms impede the penetration and killing action of the antibiotic tobramycin, illustrating their potential clinical significance. Our findings highlight the compositional and structural variety of P. aeruginosa biofilm aggregates.
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Delfino D, Mori G, Rivetti C, Grigoletto A, Bizzotto G, Cavozzi C, Malatesta M, Cavazzini D, Pasut G, Percudani R. Actin-Resistant DNase1L2 as a Potential Therapeutics for CF Lung Disease. Biomolecules 2021; 11:biom11030410. [PMID: 33802146 PMCID: PMC8002113 DOI: 10.3390/biom11030410] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/02/2021] [Accepted: 03/05/2021] [Indexed: 02/07/2023] Open
Abstract
In cystic fibrosis (CF), the accumulation of viscous lung secretions rich in DNA and actin is a major cause of chronic inflammation and recurrent infections leading to airway obstruction. Mucolytic therapy based on recombinant human DNase1 reduces CF mucus viscosity and promotes airway clearance. However, the marked susceptibility to actin inhibition of this enzyme prompts the research of alternative treatments that could overcome this limitation. Within the human DNase repertoire, DNase1L2 is ideally suited for this purpose because it exhibits metal-dependent endonuclease activity on plasmid DNA in a broad range of pH with acidic optimum and is minimally inhibited by actin. When tested on CF artificial mucus enriched with actin, submicromolar concentrations of DNase1L2 reduces mucus viscosity by 50% in a few seconds. Inspection of superimposed model structures of DNase1 and DNase1L2 highlights differences at the actin-binding interface that justify the increased resistance of DNase1L2 toward actin inhibition. Furthermore, a PEGylated form of the enzyme with preserved enzymatic activity was obtained, showing interesting results in terms of activity. This work represents an effort toward the exploitation of natural DNase variants as promising alternatives to DNase1 for the treatment of CF lung disease.
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Affiliation(s)
- Danila Delfino
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
| | - Giulia Mori
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
- Correspondence: (G.M.); (C.R.); (G.P.)
| | - Claudio Rivetti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
- Correspondence: (G.M.); (C.R.); (G.P.)
| | - Antonella Grigoletto
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy; (A.G.); (G.B.)
| | - Gloria Bizzotto
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy; (A.G.); (G.B.)
| | - Cristian Cavozzi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
| | - Marco Malatesta
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
| | - Davide Cavazzini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
| | - Gianfranco Pasut
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy; (A.G.); (G.B.)
- Correspondence: (G.M.); (C.R.); (G.P.)
| | - Riccardo Percudani
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (D.D.); (C.C.); (M.M.); (D.C.); (R.P.)
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Mathew AA, Panonnummal R. 'Magnesium'-the master cation-as a drug-possibilities and evidences. Biometals 2021; 34:955-986. [PMID: 34213669 PMCID: PMC8249833 DOI: 10.1007/s10534-021-00328-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 06/19/2021] [Indexed: 02/06/2023]
Abstract
Magnesium (Mg2+) is the 2nd most abundant intracellular cation, which participates in various enzymatic reactions; there by regulating vital biological functions. Magnesium (Mg2+) can regulate several cations, including sodium, potassium, and calcium; it consequently maintains physiological functions like impulse conduction, blood pressure, heart rhythm, and muscle contraction. But, it doesn't get much attention in account with its functions, making it a "Forgotten cation". Like other cations, maintenance of the normal physiological level of Mg2+ is important. Its deficiency is associated with various diseases, which point out to the importance of Mg2+ as a drug. The roles of Mg2+ such as natural calcium antagonist, glutamate NMDA receptor blocker, vasodilator, antioxidant and anti-inflammatory agent are responsible for its therapeutic benefits. Various salts of Mg2+ are currently in clinical use, but their application is limited. This review collates all the possible mechanisms behind the behavior of magnesium as a drug at different disease conditions with clinical shreds of evidence.
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Affiliation(s)
- Aparna Ann Mathew
- Amrita School of Pharmacy, Amrita Institute of Medical Science & Research Centre, Amrita VishwaVidyapeetham, Kochi, 682041, India
| | - Rajitha Panonnummal
- Amrita School of Pharmacy, Amrita Institute of Medical Science & Research Centre, Amrita VishwaVidyapeetham, Kochi, 682041, India.
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Lotlikar SR, Kayastha BB, Vullo D, Khanam SS, Braga RE, Murray AB, McKenna R, Supuran CT, Patrauchan MA. Pseudomonas aeruginosa β-carbonic anhydrase, psCA1, is required for calcium deposition and contributes to virulence. Cell Calcium 2019; 84:102080. [PMID: 31589941 DOI: 10.1016/j.ceca.2019.102080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/16/2019] [Accepted: 09/07/2019] [Indexed: 01/07/2023]
Abstract
Calcification of soft tissue leads to serious diseases and has been associated with bacterial chronic infections. However, the origin and the molecular mechanisms of calcification remain unclear. Here we hypothesized that a human pathogen Pseudomonas aeruginosa deposits extracellular calcium, a process requiring carbonic anhydrases (CAs). Transmission electron microscopy confirmed the formation of 0.1-0.2 μm deposits by P. aeruginosa PAO1 growing at 5 mM CaCl2, and X-ray elemental analysis confirmed they contain calcium. Quantitative analysis of deposited calcium showed that PAO1 deposits 0.35 and 0.75 mM calcium/mg protein when grown at 5 mM and 10 mM CaCl2, correspondingly. Fluorescent microscopy indicated that deposition initiates at the cell surface. We have previously characterized three PAO1 β-class CAs: psCA1, psCA2, and psCA3 that hydrate CO2 to HCO3-, among which psCA1 showed the highest catalytic activity (Lotlikar et. al. 2013). According to immunoblot and RT-qPCR, growth at elevated calcium levels increases the expression of psCA1. Analyses of the deletion mutants lacking one, two or all three psCA genes, determined that psCA1 plays a major role in calcium deposition and contributes to the pathogen's virulence. In-silico modeling of the PAO1 β-class CAs identified four amino acids that differ in psCA1 compared to psCA2, and psCA3 (T59, A61A, A101, and A108), and these differences may play a role in catalytic rate and thus calcium deposition. A series of inhibitors were tested against the recombinant psCA1, among which aminobenzene sulfonamide (ABS) and acetazolamide (AAZ), which inhibited psCA1 catalytic activity with KIs of 19 nM and 37 nM, correspondingly. The addition of ABS and AAZ to growing PAO1 reduced calcium deposition by 41 and 78, respectively. Hence, for the first time, we showed that the β-CA psCA1 in P. aeruginosa contributes to virulence likely by enabling calcium salt deposition, which can be partially controlled by inhibiting its catalytic activity.
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Affiliation(s)
- Shalaka R Lotlikar
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Daniela Vullo
- Università degli Studi di Firenze, Polo Scientifico, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Sharmily S Khanam
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Reygan E Braga
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Akilah B Murray
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Polo Scientifico, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
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Abstract
Human deoxyribonuclease I (DNase I) is an endonuclease that catalyzes the hydrolysis of extracellular DNA and is just one of the numerous types of nucleases found in nature. The enzymatic mechanism for a single turnover is reasonably well understood based on biochemical and structural studies that are consistent with divalent metal ion dependent nonspecific nicking of a phosphodiester bond in one of the strands of double stranded DNA. Recombinant human DNase I (rhDNase I, rhDNase, Pulmozyme®, dornase alfa) has been expressed in mammalian cell culture in Chinese hamster ovary cells and developed clinically where it is aerosolized into the airways for treatment of pulmonary disease in patients with cystic fibrosis (CF). rhDNase I hydrolyzes the DNA in purulent sputum of CF patients and reduces sputum viscoelasticity. Reduction of high molecular weight DNA into smaller fragments by treatment with aerosolized rhDNase I has been proposed as the mechanism to reduce the mucus viscosity and improve mucus clearability from obstructed airways in patients. The improved clearance of the purulent mucus enhances pulmonary function and reduces recurrent exacerbations of respiratory symptoms. rhDNase I was approved for clinical use in 1993 and has been widely used as a safe and effective therapy for CF patients. The use of rhDNase I has also been investigated in other diseases where exogenous DNA has been implicated in the disease pathology.
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Kim SK, Park SJ, Li XH, Choi YS, Im DS, Lee JH. Bacterial ornithine lipid, a surrogate membrane lipid under phosphate-limiting conditions, plays important roles in bacterial persistence and interaction with host. Environ Microbiol 2018; 20:3992-4008. [PMID: 30252196 DOI: 10.1111/1462-2920.14430] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 09/21/2018] [Accepted: 09/21/2018] [Indexed: 11/30/2022]
Abstract
Ornithine lipids (OLs) are bacteria-specific lipids that are found in the outer membrane of Gram (-) bacteria and increase as surrogates of phospholipids under phosphate-limited environmental conditions. We investigated the effects of OL increase in bacterial membranes on pathogen virulence and the host immune response. In Pseudomonas aeruginosa, we increased OL levels in membranes by overexpressing the OL-synthesizing operon (olsBA). These increases changed the bacterial surface charge and hydrophobicity, which reduced bacterial susceptibility to antibiotics and antimicrobial peptides (AMPs), interfered with the binding of macrophages to bacterial cells and enhanced bacterial biofilm formation. When grown under low phosphate conditions, P. aeruginosa became more persistent in the treatment of antibiotics and AMPs in an olsBA-dependent manner. While OLs increased persistence, they attenuated P. aeruginosa virulence; in host cells, they reduced the production of inflammatory factors (iNOS, COX-2, PGE2 and nitric oxide) and increased intracellular Ca2+ release. Exogenously added OL had similar effects on P. aeruginosa and host cells. Our results suggest that bacterial OL plays important roles in bacteria-host interaction in a way that enhances bacterial persistence and develops chronic adaptation to infection.
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Affiliation(s)
- Soo-Kyoung Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, 609-735, South Korea
| | - Soo-Jin Park
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, 609-735, South Korea
| | - Xi-Hui Li
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, 609-735, South Korea
| | - Yu-Sang Choi
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, 609-735, South Korea
| | - Dong-Soon Im
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, 609-735, South Korea
| | - Joon-Hee Lee
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan, 609-735, South Korea
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Impact of PEGylation on the mucolytic activity of recombinant human deoxyribonuclease I in cystic fibrosis sputum. Clin Sci (Lond) 2018; 132:1439-1452. [PMID: 29871879 DOI: 10.1042/cs20180315] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 04/13/2018] [Accepted: 06/04/2018] [Indexed: 12/28/2022]
Abstract
Highly viscous mucus and its impaired clearance characterize the lungs of patients with cystic fibrosis (CF). Pulmonary secretions of patients with CF display increased concentrations of high molecular weight components such as DNA and actin. Recombinant human deoxyribonuclease I (rhDNase) delivered by inhalation cleaves DNA filaments contained in respiratory secretions and thins them. However, rapid clearance of rhDNase from the lungs implies a daily administration and thereby a high therapy burden and a reduced patient compliance. A PEGylated version of rhDNase could sustain the presence of the protein within the lungs and reduce its administration frequency. Here, we evaluated the enzymatic activity of rhDNase conjugated to a two-arm 40 kDa polyethylene glycol (PEG40) in CF sputa. Rheology data indicated that both rhDNase and PEG40-rhDNase presented similar mucolytic activity in CF sputa, independently of the purulence of the sputum samples as well as of their DNA, actin and ions contents. The macroscopic appearance of the samples correlated with the DNA content of the sputa: the more purulent the sample, the higher the DNA concentration. Finally, quantification of the enzymes in CF sputa following rheology measurement suggests that PEGylation largely increases the stability of rhDNase in CF respiratory secretions, since 24-fold more PEG40-rhDNase than rhDNase was recovered from the samples. The present results are considered positive and provide support to the continuation of the research on a long acting version of rhDNase to treat CF lung disease.
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Pseudomonas aeruginosa Magnesium Transporter MgtE Inhibits Type III Secretion System Gene Expression by Stimulating rsmYZ Transcription. J Bacteriol 2017; 199:JB.00268-17. [PMID: 28847924 DOI: 10.1128/jb.00268-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/23/2017] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa causes numerous acute and chronic opportunistic infections in humans. One of its most formidable weapons is a type III secretion system (T3SS), which injects powerful toxins directly into host cells. The toxins lead to cell dysfunction and, ultimately, cell death. Identification of regulatory pathways that control T3SS gene expression may lead to the discovery of novel therapeutics to treat P. aeruginosa infections. In a previous study, we found that expression of the magnesium transporter gene mgtE inhibits T3SS gene transcription. MgtE-dependent inhibition appeared to interfere with the synthesis or function of the master T3SS transcriptional activator ExsA, although the exact mechanism was unclear. We now demonstrate that mgtE expression acts through the GacAS two-component system to activate rsmY and rsmZ transcription. This event ultimately leads to inhibition of exsA translation. This inhibitory effect is specific to exsA as translation of other genes in the exsCEBA operon is not inhibited by mgtE Moreover, our data reveal that MgtE acts solely through this pathway to regulate T3SS gene transcription. Our study reveals an important mechanism that may allow P. aeruginosa to fine-tune T3SS activity in response to certain environmental stimuli.IMPORTANCE The type III secretion system (T3SS) is a critical virulence factor utilized by numerous Gram-negative bacteria, including Pseudomonas aeruginosa, to intoxicate and kill host cells. Elucidating T3SS regulatory mechanisms may uncover targets for novel anti-P. aeruginosa therapeutics and provide deeper understanding of bacterial pathogenesis. We previously found that the magnesium transporter MgtE inhibits T3SS gene transcription in P. aeruginosa In this study, we describe the mechanism of MgtE-dependent inhibition of the T3SS. Our report also illustrates how MgtE might respond to environmental cues, such as magnesium levels, to fine-tune T3SS gene expression.
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Yang R, Wei T, Goldberg H, Wang W, Cullion K, Kohane DS. Getting Drugs Across Biological Barriers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:10.1002/adma.201606596. [PMID: 28752600 PMCID: PMC5683089 DOI: 10.1002/adma.201606596] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 05/30/2017] [Indexed: 05/13/2023]
Abstract
The delivery of drugs to a target site frequently involves crossing biological barriers. The degree and nature of the impediment to flux, as well as the potential approaches to overcoming it, depend on the tissue, the drug, and numerous other factors. Here an overview of approaches that have been taken to crossing biological barriers is presented, with special attention to transdermal drug delivery. Technology and knowledge pertaining to addressing these issues in a variety of organs could have a significant clinical impact.
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Affiliation(s)
- Rong Yang
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Tuo Wei
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Hannah Goldberg
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Weiping Wang
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Kathleen Cullion
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Daniel S Kohane
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
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De Boeck K, Amaral MD. Progress in therapies for cystic fibrosis. THE LANCET RESPIRATORY MEDICINE 2016; 4:662-674. [DOI: 10.1016/s2213-2600(16)00023-0] [Citation(s) in RCA: 254] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 12/19/2022]
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16
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Santi M, Milani GP, Simonetti GD, Fossali EF, Bianchetti MG, Lava SAG. Magnesium in cystic fibrosis--Systematic review of the literature. Pediatr Pulmonol 2016; 51:196-202. [PMID: 26663706 DOI: 10.1002/ppul.23356] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 11/05/2015] [Accepted: 11/21/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND The metabolism of sodium, potassium, and chloride and the acid-base balance are sometimes altered in cystic fibrosis. Textbooks and reviews only marginally address the homeostasis of magnesium in cystic fibrosis. METHODS We performed a search of the Medical Subject Headings terms (cystic fibrosis OR mucoviscidosis) AND (magnesium OR hypomagnes[a]emia) in the US National Library of Medicine and Excerpta Medica databases. RESULTS We identified 25 reports dealing with magnesium and cystic fibrosis. The results of the review may be summarized as follows. First, hypomagnesemia affects more than half of the cystic fibrosis patients with advanced disease; second, magnesemia, which is normally age-independent, relevantly decreases with age in cystic fibrosis; third, aminoglycoside antimicrobials frequently induce both acute and chronic renal magnesium-wasting; fourth, sweat magnesium concentration was normal in cystic fibrosis patients; fifth, limited data suggest the existence of an impaired intestinal magnesium balance. Finally, stimulating observations suggest that magnesium supplements might achieve an improvement in respiratory muscle strength and mucolytic activity of both recombinant and endogenous deoxyribonuclease. CONCLUSIONS The first comprehensive review of the literature confirms that, despite being one of the most prevalent minerals in the body, the importance of magnesium in cystic fibrosis is largely overlooked. In these patients, hypomagnesemia should be sought once a year. Furthermore, the potential of supplementation with this cation deserves more attention.
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Affiliation(s)
| | - Gregorio P Milani
- Department of Pediatric Emergency, Foundation IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo D Simonetti
- Pediatric Department of Southern Switzerland.,University Children's Hospital of Berne, University of Berne, Switzerland
| | - Emilio F Fossali
- Department of Pediatric Emergency, Foundation IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Sebastiano A G Lava
- Pediatric Department of Southern Switzerland.,University Children's Hospital of Berne, University of Berne, Switzerland
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The Pseudomonas aeruginosa PAO1 Two-Component Regulator CarSR Regulates Calcium Homeostasis and Calcium-Induced Virulence Factor Production through Its Regulatory Targets CarO and CarP. J Bacteriol 2016; 198:951-63. [PMID: 26755627 DOI: 10.1128/jb.00963-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/31/2015] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED Pseudomonas aeruginosa is an opportunistic human pathogen that causes severe, life-threatening infections in patients with cystic fibrosis (CF), endocarditis, wounds, or artificial implants. During CF pulmonary infections, P. aeruginosa often encounters environments where the levels of calcium (Ca(2+)) are elevated. Previously, we showed that P. aeruginosa responds to externally added Ca(2+) through enhanced biofilm formation, increased production of several secreted virulence factors, and by developing a transient increase in the intracellular Ca(2+) level, followed by its removal to the basal submicromolar level. However, the molecular mechanisms responsible for regulating Ca(2+)-induced virulence factor production and Ca(2+) homeostasis are not known. Here, we characterized the genome-wide transcriptional response of P. aeruginosa to elevated [Ca(2+)] in both planktonic cultures and biofilms. Among the genes induced by CaCl2 in strain PAO1 was an operon containing the two-component regulator PA2656-PA2657 (here called carS and carR), while the closely related two-component regulators phoPQ and pmrAB were repressed by CaCl2 addition. To identify the regulatory targets of CarSR, we constructed a deletion mutant of carR and performed transcriptome analysis of the mutant strain at low and high [Ca(2+)]. Among the genes regulated by CarSR in response to CaCl2 are the predicted periplasmic OB-fold protein, PA0320 (here called carO), and the inner membrane-anchored five-bladed β-propeller protein, PA0327 (here called carP). Mutations in both carO and carP affected Ca(2+) homeostasis, reducing the ability of P. aeruginosa to export excess Ca(2+). In addition, a mutation in carP had a pleotropic effect in a Ca(2+)-dependent manner, altering swarming motility, pyocyanin production, and tobramycin sensitivity. Overall, the results indicate that the two-component system CarSR is responsible for sensing high levels of external Ca(2+) and responding through its regulatory targets that modulate Ca(2+) homeostasis, surface-associated motility, and the production of the virulence factor pyocyanin. IMPORTANCE During infectious disease, Pseudomonas aeruginosa encounters environments with high calcium (Ca(2+)) concentrations, yet the cells maintain intracellular Ca(2+) at levels that are orders of magnitude less than that of the external environment. In addition, Ca(2+) signals P. aeruginosa to induce the production of several virulence factors. Compared to eukaryotes, little is known about how bacteria maintain Ca(2+) homeostasis or how Ca(2+) acts as a signal. In this study, we identified a two-component regulatory system in P. aeruginosa PAO1, termed CarRS, that is induced at elevated Ca(2+) levels. CarRS modulates Ca(2+) signaling and Ca(2+) homeostasis through its regulatory targets, CarO and CarP. The results demonstrate that P. aeruginosa uses a two-component regulatory system to sense external Ca(2+) and relays that information for Ca(2+)-dependent cellular processes.
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev 2015; 95:1-46. [PMID: 25540137 DOI: 10.1152/physrev.00012.2014] [Citation(s) in RCA: 886] [Impact Index Per Article: 98.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Chekabab SM, Harel J, Dozois CM. Interplay between genetic regulation of phosphate homeostasis and bacterial virulence. Virulence 2014; 5:786-93. [PMID: 25483775 DOI: 10.4161/viru.29307] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacterial pathogens, including those of humans, animals, and plants, encounter phosphate (Pi)-limiting or Pi-rich environments in the host, depending on the site of infection. The environmental Pi-concentration results in modulation of expression of the Pho regulon that allows bacteria to regulate phosphate assimilation pathways accordingly. In many cases, modulation of Pho regulon expression also results in concomitant changes in virulence phenotypes. Under Pi-limiting conditions, bacteria use the transcriptional-response regulator PhoB to translate the Pi starvation signal sensed by the bacterium into gene activation or repression. This regulator is employed not only for the maintenance of bacterial Pi homeostasis but also to differentially regulate virulence. The Pho regulon is therefore not only a regulatory circuit of phosphate homeostasis but also plays an important adaptive role in stress response and bacterial virulence. Here we focus on recent findings regarding the mechanisms of gene regulation that underlie the virulence responses to Pi stress in Vibrio cholerae, Pseudomonas spp., and pathogenic E. coli.
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Affiliation(s)
- Samuel Mohammed Chekabab
- a Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA); Université de Montréal; Faculté de Médecine Vétérinaire ; Saint-Hyacinthe , QC Canada
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Coffey BM, Akhand SS, Anderson GG. MgtE is a dual-function protein in Pseudomonas aeruginosa. MICROBIOLOGY-SGM 2014; 160:1200-1213. [PMID: 24722909 DOI: 10.1099/mic.0.075275-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa causes a wide range of infections, including chronic biofilm infections in the lungs of individuals with cystic fibrosis. We previously found that the inner-membrane protein MgtE can function both as a magnesium transporter and a virulence modulator, although the exact mechanism governing these activities is unclear. To address this issue, we carried out an experimental characterization of P. aeruginosa MgtE and generated a computer-rendered model. Our in silico analysis demonstrated the structural similarity of P. aeruginosa MgtE to that of the crystal structure of MgtE in Thermus thermophilus. Experimentally, we verified that MgtE is not essential for growth and found that it may not be involved directly in biofilm formation, even under low-magnesium conditions. We demonstrated both magnesium transport and cytotoxicity-regulating functions, and showed that magnesium-binding sites in the connecting helix region of MgtE are vital in coupling these two functions. Furthermore, limiting magnesium environments stimulated mgtE transcriptional responses. Our results suggested that MgtE might play an important role in linking magnesium availability to P. aeruginosa pathogenesis.
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Affiliation(s)
- Barbara M Coffey
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Saeed S Akhand
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Gregory G Anderson
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
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Investigating the role of matrix components in protection of Burkholderia cepacia complex biofilms against tobramycin. J Cyst Fibros 2014; 13:56-62. [DOI: 10.1016/j.jcf.2013.07.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/04/2013] [Accepted: 07/20/2013] [Indexed: 11/21/2022]
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Dubois AV, Midoux P, Gras D, Si-Tahar M, Bréa D, Attucci S, Khelloufi MK, Ramphal R, Diot P, Gauthier F, Hervé V. Poly-L-Lysine compacts DNA, kills bacteria, and improves protease inhibition in cystic fibrosis sputum. Am J Respir Crit Care Med 2013; 188:703-9. [PMID: 23947381 DOI: 10.1164/rccm.201305-0912oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RATIONALE Neutrophil serine proteases in cystic fibrosis (CF) lung secretions partially resist inhibition by natural and exogenous inhibitors, mostly because DNA impairs their control. Cationic polypeptides display the property of condensing DNA and retain antimicrobial properties. We hypothesized that DNA condensation by cationic polypeptides in CF sputum would result in a better control of CF inflammation and infection. OBJECTIVES We examined whether poly-L-lysine would compact DNA in CF lung secretions and liquefy CF sputum, improve the control of extracellular proteases by exogenous inhibitors, and whether it displays antibacterial properties toward CF-associated bacteria. METHODS We used fluorogenic methods to measure proteolytic activities and inhibition by protease inhibitors in whole sputum homogenates from patients with CF before and after treatment with poly-L-lysine. Antibacterial properties of poly-L-lysine were measured in bacterial cultures and in whole CF sputum. Poly-L-lysine toxicity was evaluated after aerosolization by histologic analysis, flow cytometry, and quantification of proinflammatory cytokines. MEASUREMENTS AND MAIN RESULTS Poly-L-lysine compacts CF sputum DNA, generating a liquid phase that improves ciliary beating frequency at the lung epithelial surface, and allows the control of neutrophil elastase and cathepsin G by their natural inhibitors. It retains antimicrobial properties against Pseudomonas aeruginosa and Staphylococcus aureus at doses that induce no inflammation in the mouse lung after aerosol administration. CONCLUSIONS Poly-L-lysine may be an alternative to dornase-α to liquefy sputum with added benefits because it helps natural inhibitors to better control the deleterious effects of extracellularly released neutrophil serine proteases and has the ability to kill bacteria in CF sputum.
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23
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Lewenza S. Extracellular DNA-induced antimicrobial peptide resistance mechanisms in Pseudomonas aeruginosa. Front Microbiol 2013; 4:21. [PMID: 23419933 PMCID: PMC3572637 DOI: 10.3389/fmicb.2013.00021] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 01/28/2013] [Indexed: 12/17/2022] Open
Abstract
Extracellular DNA (eDNA) is in the environment, bodily fluids, in the matrix of biofilms, and accumulates at infection sites. eDNA can function as a nutrient source, a universal biofilm matrix component, and an innate immune effector in eDNA traps. In biofilms, eDNA is required for attachment, aggregation, and stabilization of microcolonies. We have recently shown that eDNA can sequester divalent metal cations, which has interesting implications on antibiotic resistance. eDNA binds metal cations and thus activates the Mg2+-responsive PhoPQ and PmrAB two-component systems. In Pseudomonas aeruginosa and many other Gram-negative bacteria, the PhoPQ/PmrAB systems control various genes required for virulence and resisting killing by antimicrobial peptides (APs), including the pmr genes (PA3552–PA3559) that are responsible for the addition of aminoarabinose to lipid A. The PA4773–PA4775 genes are a second DNA-induced cluster and are required for the production of spermidine on the outer surface, which protects the outer membrane from AP treatment. Both modifications mask the negative surface charges and limit membrane damage by APs. DNA-enriched biofilms or planktonic cultures have increased antibiotic resistance phenotypes to APs and aminoglycosides. These dual antibiotic resistance and immune evasion strategies may be expressed in DNA-rich environments and contribute to long-term survival.
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Affiliation(s)
- Shawn Lewenza
- Snyder Institute for Chronic Diseases, University of Calgary Calgary, AB, Canada ; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary Calgary, AB, Canada
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Parsiegla G, Noguere C, Santell L, Lazarus RA, Bourne Y. The structure of human DNase I bound to magnesium and phosphate ions points to a catalytic mechanism common to members of the DNase I-like superfamily. Biochemistry 2012; 51:10250-8. [PMID: 23215638 DOI: 10.1021/bi300873f] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recombinant human DNase I (Pulmozyme, dornase alfa) is used for the treatment of cystic fibrosis where it improves lung function and reduces the number of exacerbations. The physiological mechanism of action is thought to involve the reduction of the viscoelasticity of cystic fibrosis sputum by hydrolyzing high concentrations of DNA into low-molecular mass fragments. Here we describe the 1.95 Å resolution crystal structure of recombinant human DNase I (rhDNase I) in complex with magnesium and phosphate ions, both bound in the active site. Complementary mutagenesis data of rhDNase I coupled to a comprehensive structural analysis of the DNase I-like superfamily argue for the key catalytic role of Asn7, which is invariant among mammalian DNase I enzymes and members of this superfamily, through stabilization of the magnesium ion coordination sphere. Overall, our combined structural and mutagenesis data suggest the occurrence of a magnesium-assisted pentavalent phosphate transition state in human DNase I during catalysis, where Asp168 may play a key role as a general catalytic base.
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Affiliation(s)
- Goetz Parsiegla
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université and CNRS UMR 7257, Parc Scientifique et Technonlogique de Luminy, Case 932, 163 Avenue de Luminy, 13288 Marseille cedex 09, France.
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Wilms EB, Touw DJ, Heijerman HGM, van der Ent CK. Azithromycin maintenance therapy in patients with cystic fibrosis: a dose advice based on a review of pharmacokinetics, efficacy, and side effects. Pediatr Pulmonol 2012; 47:658-65. [PMID: 22684985 DOI: 10.1002/ppul.21620] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 10/27/2011] [Indexed: 01/31/2023]
Abstract
Azithromycin maintenance therapy results in improvement of respiratory function in patients with cystic fibrosis (CF). In azithromycin maintenance therapy, several dosing schemes are applied. In this review, we combine current knowledge about azithromycin pharmacokinetics with the dosing schedules used in clinical trials in order to come to a dosing advise which could be generally applicable. We used data from a recently updated Cochrane meta analysis (2011), the reports of clinical trials and pharmacokinetic studies. Based on these data, it was concluded that a dose level of 22-30 mg/kg/week is the lowest dose level with proven efficacy. Due to the extended half-life in patients with CF, the weekly dose of azithromycin can be divided in one to seven dosing moments, depending on patient preference and gastro-intestinal tolerance. No important side effects or interactions with other CF-related drugs have been documented so far.
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Affiliation(s)
- Erik B Wilms
- Central Hospital Pharmacy, The Hague, The Netherlands.
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Gontijo-Amaral C, Guimarães EV, Camargos P. Oral magnesium supplementation in children with cystic fibrosis improves clinical and functional variables: a double-blind, randomized, placebo-controlled crossover trial. Am J Clin Nutr 2012; 96:50-6. [PMID: 22648717 DOI: 10.3945/ajcn.112.034207] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Magnesium is one of the most important minerals in the body. Although some studies reported that patients with cystic fibrosis (CF) lack magnesium, no international study has assessed the importance of oral magnesium supplementation in CF patients. OBJECTIVE We prospectively investigated the long-term effect of oral magnesium supplementation on respiratory muscle strength by using manuvacuometry and the Shwachman-Kulczycki (SK) score among children and adolescents with CF. DESIGN This double-blind, randomized, placebo-controlled crossover study included 44 CF patients (aged 7-19 y; 20 males) who were randomly assigned to receive magnesium (n = 22; 300 mg/d) or placebo (n = 22) for 8 wk with a 4-wk washout period between trials. All patients were undergoing conventional treatment of CF. The experimental protocol included clinical evaluation, assessment of urinary concentration of magnesium, and manuvacuometric measurements [maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP)]. MIP was the primary outcome. RESULTS Urinary magnesium increased after the administration of magnesium (change: 36.38 mg/d after magnesium compared with 0.72 mg/d after placebo; P < 0.001). Moreover, MIP and MEP significantly improved only after magnesium administration (change in MIP: 11% predicted after magnesium compared with 0.5% predicted after placebo; change in MEP: 11.9% predicted after magnesium compared with 0.8% predicted after placebo; P < 0.001 for both). Magnesium administration had a beneficial effect on clinical variables assessed by the SK score (change: 4.48 points after magnesium compared with -1.30 points after placebo; P < 0.001). CONCLUSION Oral magnesium supplementation helped improve both the SK score and respiratory muscle strength in pediatric patients with CF.
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Affiliation(s)
- Clésio Gontijo-Amaral
- Pediatrics Department, Diagnostic Support Action and Research Center (NUPAD), Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil.
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Pressler T. Review of recombinant human deoxyribonuclease (rhDNase) in the management of patients with cystic fibrosis. Biologics 2011; 2:611-7. [PMID: 19707442 PMCID: PMC2727891 DOI: 10.2147/btt.s3052] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The most important problem in cystic fibrosis (CF) lung disease is chronic airway inflammation and infection, which starts early in life. To prevent severe lung damage, it is important to mobilize as much sputum as possible from the lung on a daily basis. RhDNase is an enzyme that breaks down DNA strands in airway secretions, hydrolyzes the DNA present in sputum/mucus of CF patients, reducing viscosity in the lungs and promoting secretion clearance. Several well performed trials have proven its efficacy in young CF patients with mild disease as well as in older patients with more advanced lung disease. Daily inhalation of this agent slows down lung function decline and decreases the frequency of respiratory exacerbations. The drug is well tolerated by most patients independent of the severity of lung disease.
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Affiliation(s)
- Tacjana Pressler
- CF Centre, Dept. of Pediatrics, Rigshospitalet, University of Copenhagen Denmark
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Bakker EM, Tiddens HAWM. Pharmacology, clinical efficacy and safety of recombinant human DNase in cystic fibrosis. Expert Rev Respir Med 2010; 1:317-29. [PMID: 20477171 DOI: 10.1586/17476348.1.3.317] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recombinant human DNase (rhDNase) is a mucolytic agent that is primarily used to improve mucociliary clearance in cystic fibrosis (CF). rhDNase is a recombinant human enzyme that is synthesized in a Chinese hamster ovary cell line. rhDNase enzymatically cleaves extracellular DNA into molecules of shorter length. CF sputum shows high concentrations of DNA released by disintegrating inflammatory cells. Free DNA contributes to the abnormally high viscosity of CF sputum and therefore forms an important target in the treatment of CF lung disease. Clinical studies have shown that daily nebulization of rhDNase is associated with an increase in lung function and a decrease in the frequency of exacerbations in patients with CF.
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Affiliation(s)
- E M Bakker
- Erasmus MC - Sophia Children's Hospital, Department of Pediatric Respiratory Medicine, Room Sb-2666, Dr. Molewaterplein 60, 3015 GJ Rotterdam, The Netherlands.
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Rosenecker J, Naundorf S, Rudolph C. Airway surface liquid contains endogenous DNase activity which can be activated by exogenous magnesium. Eur J Med Res 2009; 14:304-8. [PMID: 19661013 PMCID: PMC3474179 DOI: 10.1186/2047-783x-14-7-304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Introduction The removal of highly viscous mucus from the airways is an important task in the treatment of chronic lung disease like in cystic fibrosis. The inhalation of recombinant human DNase-I (rhDNase-I) is used to facilitate the removal of tenacious airway secretions in different lung diseases and especially in CF. Little is known about endogenous DNase activity in the airway surface liquid. Therefore, we analysed bronchoalveolar lavage fluid (BAL) and exhaled breath condensate (EBC) for the presence of endogenous DNase activity. Methods The degradation of plasmid DNA by BAL from patients who had diagnostic bronchoscopy and bronchoalveolar lavage was analyzed. In a group of CF patients and healthy control volunteers the exhaled breath condensate was obtained and also analyzed for the ability to degrade plasmid DNA. In addition, the ability of magnesium to activate endogenous DNase activity in BAL and exhaled breath condensate was investigated. Results The analyzed BAL samples degraded plasmid DNA only after preincubation with magnesium. When analyzing the exhaled breath condensate the samples obtained from the healthy volunteers showed no DNase activity even after preincubation with magnesium, whereas in one of the two samples obtained from CF patients we found a DNase activity after preincubation with magnesium. Conclusion Increasing the magnesium concentration in the airway surface liquid by aerosolisation of magnesium solutions or oral magnesium supplements could improve the removal of highly viscous mucus in chronic lung disease by activating endogenous DNase activity.
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Affiliation(s)
- Joseph Rosenecker
- Department of Pediatrics, University of Munich, Lindwurmstr. 2a, 80337 Munich, Germany.
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Sanders N, Rudolph C, Braeckmans K, De Smedt SC, Demeester J. Extracellular barriers in respiratory gene therapy. Adv Drug Deliv Rev 2009; 61:115-27. [PMID: 19146894 PMCID: PMC7103358 DOI: 10.1016/j.addr.2008.09.011] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 09/22/2008] [Indexed: 12/11/2022]
Abstract
Respiratory gene therapy has been considered for the treatment of a broad range of pulmonary disorders. However, respiratory secretions form an important barrier towards the pulmonary delivery of therapeutic nucleic acids. In this review we will start with a brief description of the biophysical properties of respiratory mucus and alveolar fluid. This must allow the reader to gain insights into the mechanisms by which respiratory secretions may impede the gene transfer efficiency of nucleic acid containing nanoparticles (NANs). Subsequently, we will summarize the efforts that have been done to understand the barrier properties of respiratory mucus and alveolar fluid towards the respiratory delivery of therapeutic nucleic acids. Finally, new and current strategies that can overcome the inhibitory effects of respiratory secretions are discussed.
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Lai SK, Wang YY, Hanes J. Mucus-penetrating nanoparticles for drug and gene delivery to mucosal tissues. Adv Drug Deliv Rev 2009; 61:158-71. [PMID: 19133304 PMCID: PMC2667119 DOI: 10.1016/j.addr.2008.11.002] [Citation(s) in RCA: 1204] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 11/21/2008] [Indexed: 12/31/2022]
Abstract
Mucus is a viscoelastic and adhesive gel that protects the lung airways, gastrointestinal (GI) tract, vagina, eye and other mucosal surfaces. Most foreign particulates, including conventional particle-based drug delivery systems, are efficiently trapped in human mucus layers by steric obstruction and/or adhesion. Trapped particles are typically removed from the mucosal tissue within seconds to a few hours depending on anatomical location, thereby strongly limiting the duration of sustained drug delivery locally. A number of debilitating diseases could be treated more effectively and with fewer side effects if drugs and genes could be more efficiently delivered to the underlying mucosal tissues in a controlled manner. This review first describes the tenacious mucus barrier properties that have precluded the efficient penetration of therapeutic particles. It then reviews the design and development of new mucus-penetrating particles that may avoid rapid mucus clearance mechanisms, and thereby provide targeted or sustained drug delivery for localized therapies in mucosal tissues.
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Affiliation(s)
- Samuel K. Lai
- Department of Chemical & Biomolecular Engineering (JH Primary Appointment), Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
- Institute for NanoBioTechnology, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
| | - Ying-Ying Wang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Justin Hanes
- Department of Chemical & Biomolecular Engineering (JH Primary Appointment), Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
- Institute for NanoBioTechnology, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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Palmer KL, Aye LM, Whiteley M. Nutritional cues control Pseudomonas aeruginosa multicellular behavior in cystic fibrosis sputum. J Bacteriol 2007; 189:8079-87. [PMID: 17873029 PMCID: PMC2168676 DOI: 10.1128/jb.01138-07] [Citation(s) in RCA: 445] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The sputum (mucus) layer of the cystic fibrosis (CF) lung is a complex substrate that provides Pseudomonas aeruginosa with carbon and energy to support high-density growth during chronic colonization. Unfortunately, the CF lung sputum layer has been difficult to mimic in animal models of CF disease, and mechanistic studies of P. aeruginosa physiology during growth in CF sputum are hampered by its complexity. In this study, we performed chromatographic and enzymatic analyses of CF sputum to develop a defined, synthetic CF sputum medium (SCFM) that mimics the nutritional composition of CF sputum. Importantly, P. aeruginosa displays similar phenotypes during growth in CF sputum and in SCFM, including similar growth rates, gene expression profiles, carbon substrate preferences, and cell-cell signaling profiles. Using SCFM, we provide evidence that aromatic amino acids serve as nutritional cues that influence cell-cell signaling and antimicrobial activity of P. aeruginosa during growth in CF sputum.
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Affiliation(s)
- Kelli L Palmer
- Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University Station, A5000, Austin, TX 78712, USA
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Sanders NN, Eijsink VGH, van den Pangaart PS, Joost van Neerven RJ, Simons PJ, De Smedt SC, Demeester J. Mucolytic activity of bacterial and human chitinases. Biochim Biophys Acta Gen Subj 2007; 1770:839-46. [PMID: 17321686 DOI: 10.1016/j.bbagen.2007.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 01/24/2007] [Accepted: 01/25/2007] [Indexed: 11/21/2022]
Abstract
Several pulmonary pathologies, like cystic fibrosis (CF), are characterized by hypersecretion and stasis of tenacious mucus. Bacterial glycosidases are known to degrade mucins but their use as mucolytic agents is questionable. The observation that bacterial chitinases degrade mucins and the recent discovery of human chitinases, which have been proposed to be involved in the genesis of asthma, prompted us to evaluate the mucolytic properties of human derived chitinases. The effect of these human chitinases, and bacterial chitinases (positive control), on the viscoelasticity of CF sputa and on the electrophoretic mobility of human mucins was tested. Commercial bacterial chitinase drastically degraded CF sputum, while human derived chitinases did not. Accordingly, the commercial bacterial chitinase was found to degrade mucins, whereas recombinant human chitinases did not. A thorough analysis of the commercial chitinase elucidated that contaminating proteases and also nucleases assisted in the mucolytic effect. Indeed, recombinant bacterial chitinases very slightly reduced the viscoelasticity of CF sputum, but they caused a significant degradation of the CF sputum when they were combined with proteases. In conclusion, this work shows that recombinant human and recombinant bacterial chitinases have no or very low mucolytic activities, respectively. The observed mucolytic properties of commercial bacterial chitinase are due to a synergistic effect between chitinolytic and proteolytic enzymes at one hand and at the other hand also due to the presence of contaminating nucleases.
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Affiliation(s)
- Niek N Sanders
- Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
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