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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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Kovaliov M, Cohen-Karni D, Burridge KA, Mambelli D, Sloane S, Daman N, Xu C, Guth J, Kenneth Wickiser J, Tomycz N, Page RC, Konkolewicz D, Averick S. Grafting strategies for the synthesis of active DNase I polymer biohybrids. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.07.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Lam C, Santell L, Wilson B, Yim M, Louie S, Tang D, Shaw D, Chan P, Lazarus RA, Snedecor B, Misaghi S. Taming hyperactive hDNase I: Stable inducible expression of a hyperactive salt- and actin-resistant variant of human deoxyribonuclease I in CHO cells. Biotechnol Prog 2017; 33:523-533. [PMID: 28127892 DOI: 10.1002/btpr.2439] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/22/2016] [Indexed: 12/17/2022]
Abstract
While the most common causes of clonal instability are DNA copy number loss and silencing, toxicity of the expressed protein(s) may also induce clonal instability. Human DNase I (hDNase I) is used therapeutically for the treatment of cystic fibrosis (CF) and may have potential benefit for use in systemic lupus erythematosus (SLE). hDNase I is an endonuclease that catalyzes degradation of extracellular DNA and is inhibited by both salt and G-actin. Engineered versions of hDNase I, bearing multiple point mutations, which renders them Hyperactive, Salt- and Actin-Resistant (HSAR-hDNase I) have been developed previously. However, constitutive expression of HSAR-hDNase I enzymes has been very challenging and, despite considerable efforts and screening thousands of clones, no stable clone capable of constitutive expression had been obtained. Here, we developed a regulated expression system for stable expression of an HSAR-hDNase I in Chinese Hamster Ovary (CHO) cells. The HSAR-hDNase I clones were stable and, upon induction, expressed enzymatically functional protein. Our findings suggest that degradation of host's DNA mediated by HSAR-hDNase I during cell division is the likely cause of clonal instability observed in cells constitutively expressing this protein. Purified HSAR-hDNase I was both hyperactive and resistant to inhibition by salt and G-actin, resulting in an enzyme having ca. 10-fold greater specific activity and the potential to be a superior therapeutic agent to wild type (WT) hDNase I. Furthermore, the ability to regulate hDNase I expression has enabled process development improvements that achieve higher cell growth and product titers while maintaining product quality. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 32:523-533, 2017.
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Affiliation(s)
- Cynthia Lam
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
| | - Lydia Santell
- Early Discovery Biochemistry, Genentech, Inc, South San Francisco, CA, 94080
| | - Blair Wilson
- Biochemical and Cellular Pharmacology Dept., Genentech, Inc, South San Francisco, CA, 94080
| | - Mandy Yim
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
| | - Salina Louie
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
| | - Danming Tang
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
| | - David Shaw
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
| | - Pamela Chan
- Biochemical and Cellular Pharmacology Dept., Genentech, Inc, South San Francisco, CA, 94080
| | - Robert A Lazarus
- Early Discovery Biochemistry, Genentech, Inc, South San Francisco, CA, 94080
| | - Brad Snedecor
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
| | - Shahram Misaghi
- Early Stage Cell Culture, Genentech, Inc, South San Francisco, CA, 94080
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Comparative biochemical properties of vertebrate deoxyribonuclease I. Comp Biochem Physiol B Biochem Mol Biol 2012; 163:263-73. [DOI: 10.1016/j.cbpb.2012.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/26/2012] [Accepted: 07/27/2012] [Indexed: 11/18/2022]
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Manzenreiter R, Kienberger F, Marcos V, Schilcher K, Krautgartner WD, Obermayer A, Huml M, Stoiber W, Hector A, Griese M, Hannig M, Studnicka M, Vitkov L, Hartl D. Ultrastructural characterization of cystic fibrosis sputum using atomic force and scanning electron microscopy. J Cyst Fibros 2011; 11:84-92. [PMID: 21996135 DOI: 10.1016/j.jcf.2011.09.008] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Revised: 09/13/2011] [Accepted: 09/19/2011] [Indexed: 12/31/2022]
Abstract
BACKGROUND Cystic fibrosis (CF) lung disease is characterized by perpetuated neutrophilic inflammation with progressive tissue destruction. Neutrophils represent the major cellular fraction in CF airway fluids and are known to form neutrophil extracellular traps (NETs) upon stimulation. Large amounts of extracellular DNA-NETs are present in CF airway fluids. However, the structural contribution of NETs to the matrix composition of CF airway fluid remains poorly understood. We hypothesized that CF airway fluids consist of distinct DNA-NETs that are associated to subcellular structures. METHODOLOGY/PRINCIPAL FINDINGS We employed atomic force microcopy (AFM) and scanning electron microcopy to ultrastructurally characterize the nature of CF sputum and the role of NETs within the extracellular CF sputum matrix. These studies demonstrate that CF sputum is predominantly composed of a high-density meshwork of NETs and NETosis-derived material. Treatment of CF sputum with different DNases degraded CF NETs and efficiently liquefied the mucous-like structure of CF sputum. Quantitative analysis of AFM results showed the presence of three globular fractions within CF sputum and the larger two ones featured characteristics of neutrophil ectosomes. CONCLUSIONS/SIGNIFICANCE These studies suggest that excessive NET formation represents the major factor underlying the gel-like structure of CF sputum and provide evidence that CF-NETs contain ectosome-like structures that could represent targets for future therapeutic approaches.
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Affiliation(s)
- Reinhard Manzenreiter
- School of Applied Health and Social Sciences, Upper Austria University of Applied Sciences, Linz, Austria
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Kuvichkin VV. The mechanism of a nuclear pore assembly: a molecular biophysics view. J Membr Biol 2011; 241:109-16. [PMID: 21678042 DOI: 10.1007/s00232-011-9367-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 04/22/2011] [Indexed: 11/29/2022]
Abstract
The basic problem of nuclear pore assembly is the big perinuclear space that must be overcome for nuclear membrane fusion and pore creation. Our investigations of ternary complexes: DNA-PC liposomes-Mg²⁺, and modern conceptions of nuclear pore structure allowed us to introduce a new mechanism of nuclear pore assembly. DNA-induced fusion of liposomes (membrane vesicles) with a single-lipid bilayer or two closely located nuclear membranes is considered. After such fusion on the lipid bilayer surface, traces of a complex of ssDNA with lipids were revealed. At fusion of two identical small liposomes (membrane vesicles) < 100 nm in diameter, a "big" liposome (vesicle) with ssDNA on the vesicle equator is formed. ssDNA occurrence on liposome surface gives a biphasic character to the fusion kinetics. The "big" membrane vesicle surrounded by ssDNA is the base of nuclear pore assembly. Its contact with the nuclear envelope leads to fast fusion of half of the vesicles with one nuclear membrane; then ensues a fusion delay when ssDNA reaches the membrane. The next step is to turn inside out the second vesicle half and its fusion to other nuclear membrane. A hole is formed between the two membranes, and nucleoporins begin pore complex assembly around the ssDNA. The surface tension of vesicles and nuclear membranes along with the kinetic energy of a liquid inside a vesicle play the main roles in this process. Special cases of nuclear pore formation are considered: pore formation on both nuclear envelope sides, the difference of pores formed in various cell-cycle phases and linear nuclear pore clusters.
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Affiliation(s)
- Vasily V Kuvichkin
- Department of Mechanisms Reception, Institute of Cell Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
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Hida K, Lai SK, Suk JS, Won SY, Boyle MP, Hanes J. Common gene therapy viral vectors do not efficiently penetrate sputum from cystic fibrosis patients. PLoS One 2011; 6:e19919. [PMID: 21637751 PMCID: PMC3103503 DOI: 10.1371/journal.pone.0019919] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 04/14/2011] [Indexed: 02/07/2023] Open
Abstract
Norwalk virus and human papilloma virus, two viruses that infect humans at mucosal surfaces, have been found capable of rapidly penetrating human mucus secretions. Viral vectors for gene therapy of Cystic Fibrosis (CF) must similarly penetrate purulent lung airway mucus (sputum) to deliver DNA to airway epithelial cells. However, surprisingly little is known about the rates at which gene delivery vehicles penetrate sputum, including viral vectors used in clinical trials for CF gene therapy. We find that sputum spontaneously expectorated by CF patients efficiently traps two viral vectors commonly used in CF gene therapy trials, adenovirus (d∼80 nm) and adeno-associated virus (AAV serotype 5; d∼20 nm), leading to average effective diffusivities that are ∼3,000-fold and 12,000-fold slower than their theoretical speeds in water, respectively. Both viral vectors are slowed by adhesion, as engineered muco-inert nanoparticles with diameters as large as 200 nm penetrate the same sputum samples at rates only ∼40-fold reduced compared to in pure water. A limited fraction of AAV exhibit sufficiently fast mobility to penetrate physiologically thick sputum layers, likely because of the lower viscous drag and smaller surface area for adhesion to sputum constituents. Nevertheless, poor penetration of CF sputum is likely a major contributor to the ineffectiveness of viral vector based gene therapy in the lungs of CF patients observed to date.
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Affiliation(s)
- Kaoru Hida
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Samuel K. Lai
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
- Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jung Soo Suk
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sang Y. Won
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Michael P. Boyle
- Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, Maryland, United States of America
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins Adult Cystic Fibrosis Program, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Justin Hanes
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
- Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, Maryland, United States of America
- The Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Simvastatin attenuates acrolein-induced mucin production in rats: Involvement of the Ras/extracellular signal-regulated kinase pathway. Int Immunopharmacol 2010; 10:685-93. [DOI: 10.1016/j.intimp.2010.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Revised: 03/19/2010] [Accepted: 03/23/2010] [Indexed: 11/18/2022]
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Abstract
In cystic fibrosis (CF) respiratory failure caused by progressive airway obstruction and tissue damage is primarily a result of the aberrant inflammatory responses to lung infections with Pseudomonas aeruginosa. Despite considerable improvement in patient survival, conventional therapies are mainly supportive. Recent progress towards gene therapy for CF has been encouraging; however, several factors such as immune response and transduced cell turnover remain as potential limitations to CF gene therapy. As alternative gene therapy vectors for CF we examined the feasibility of using SV40-derived vectors (rSV40s) which may circumvent some of these obstacles. To accommodate the large CFTR cDNA, we removed not only SV40 Tag genes, but also all capsid genes. We therefore tested whether “gutless” rSV40s could be packaged and were able to express a functional human CFTR cDNA. Results from our in vitro analysis determined that rSV40-CFTR was able to successfully result in the expression of CFTR protein which localized to the plasma membrane and restored channel function to CFTR deficient cells. Similarly in vivo experiments delivering rSV40-CFTR to the lungs of Cftr−/− mice resulted in a reduction of the pathology associated with intra-tracheal pseudomona aeruginosa challenge. rSV40-CFTR treated mice had had less weight loss when compared to control treated mice as well as demonstrably reduced lung inflammation as evidence by histology and reduced inflammatory cytokines in the BAL. The reduction in inflammatory cytokine levels led to an evident decrease in neutrophil influx to the airways. These results indicate that further study of the application of rSV40-CFTR to CF gene therapy is warranted.
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Kater A, Henke MO, Rubin BK. The Role of DNA and Actin Polymers on the Polymer Structure and Rheology of Cystic Fibrosis Sputum and Depolymerization by Gelsolin or Thymosin Beta 4. Ann N Y Acad Sci 2007; 1112:140-53. [PMID: 17496063 DOI: 10.1196/annals.1415.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mucus clearance is the first line of pulmonary defense against inhaled irritants, microorganisms, and allergens. In health, the gel-forming mucins are the principal polymeric components of airway mucus but in cystic fibrosis (CF), the necrotic death of inflammatory and epithelial cells releases a network of copolymerized extracellular DNA and filamentous (F-) actin-producing secretions that are similar to pus and difficult to clear by cilia or airflow. The large amounts of F-actin in CF sputum suggested that thymosin beta4 (Tbeta4) or gelsolin could depolymerize the secondary polymer network of CF sputum. Dose-dependent CF sputum rheology and polymer structure were measured before and after the addition of excipient, dornase alfa, Tbeta4, gelsolin, and Tbeta4 or gelsolin with dornase for 30 min. Sputum was also incubated with Tbeta4 30 microg/mL, gelsolin 10 microg/mL or excipient for 0, 5, 10, 15, 20, or 60 min. There was a dose-dependent decrease in cohesivity with Tbeta4 and a time-dependent decrease in cohesivity at 30 microg/mL. With the combination of dornase alfa and Tbeta4 at 1.5 microg/mL, there was a 65% decrease in elasticity (P = 0.013). There was a time-dependent decrease in cohesivity (P = 0.0004) and elasticity (P = 0.047) with gelsolin and a dose-dependent fall in cohesivity (P = 0.0008). An apparent synergy of Tbeta4 or gelsolin on actin and dornase on DNA may be explained by the combined effect of actin depolymerization and DNA filament severing or by virtue of actin depolymerization increasing the effectiveness of dornase alfa.
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Affiliation(s)
- Arnon Kater
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1081, USA
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Sanders NN, Franckx H, De Boeck K, Haustraete J, De Smedt SC, Demeester J. Role of magnesium in the failure of rhDNase therapy in patients with cystic fibrosis. Thorax 2006; 61:962-8. [PMID: 17071834 PMCID: PMC2121161 DOI: 10.1136/thx.2006.060814] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND In the management of cystic fibrosis (CF), rhDNase-I inhalation is widely used to facilitate the removal of the highly viscous and elastic mucus (often called sputum) from the lungs. However, an important group of CF patients does not benefit from rhDNase-I treatment. A study was undertaken to elucidate the reason for the failure of rhDNase-I in these patients and to evaluate strategies to overcome this. METHODS The biochemical properties, physical properties, and degradation by rhDNase-I of sputum obtained from clinical responders and non-responders to rhDNase-I were compared, and the ability of magnesium to reactivate rhDNase-I in DNA solutions and in sputum was investigated. The effect of oral magnesium supplements on magnesium levels in the sputum of patients with CF was also examined. RESULTS Sputum from clinical responders was extensively degraded in vitro on incubation with rhDNase-I, while sputum from clinical non-responders was not degraded: the median decrease in sputum elasticity in the two groups was 32% and 5%, respectively. Sputum from clinical responders contained significantly higher concentrations of magnesium than sputum from non-responders (2.0 mM v 1.3 mM; p = 0.020). Sputum that could not be degraded by rhDNase-I became degradable after preincubation with magnesium. The effect of magnesium on rhDNase-I activity was mediated through actin. Oral intake of magnesium enhanced the magnesium concentration in the sputum of CF patients. CONCLUSION Increasing the magnesium concentration in sputum by, for example, oral magnesium supplements may be a promising new strategy to overcome the failure of rhDNase-I in patients with CF.
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Affiliation(s)
- N N Sanders
- Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
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Fujihara J, Hieda Y, Xue Y, Nakagami N, Imamura S, Takayama K, Kataoka K, Takeshita H. Actin-inhibition and folding of vertebrate deoxyribonuclease I are affected by mutations at residues 67 and 114. Comp Biochem Physiol B Biochem Mol Biol 2006; 143:70-5. [PMID: 16311052 DOI: 10.1016/j.cbpb.2005.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 10/10/2005] [Accepted: 10/11/2005] [Indexed: 10/25/2022]
Abstract
Amino acid (aa) residues (Val-67 and Ala-114) have been suggested as being mainly responsible for actin-binding in human and bovine deoxyribonucleases I (DNase I). This study presents evidence of these two aa mutational mechanisms, not only for actin-binding but also for folding of DNase I in mammals, reptiles and amphibians. Human and viper snake (Agkistrodon blomhoffii) enzymes are inhibited by actin, whereas porcine, rat snake (Elaphe quadrivirgata), and African clawed frog (Xenopus laevis) enzymes are not. To investigate the role of aa at 67, mutants of rat snake (Ile67Val) and viper snake (Val67Ile) enzymes were constructed. After substitution, the rat snake was inhibited by actin, while the viper snake was not. For the role of aa at 114, mutants of viper snake (Phe114Ala), rat snake (Phe114Ala), African clawed frog (Phe114Ala), and porcine (Ser114Ala/Ser114Phe) enzymes were constructed. Strikingly, the substitute mutants for viper snake, rat snake and African clawed frog expressed no protein. The porcine (Ser114Ala) enzyme was inhibited by actin, but not the porcine (Ser114Phe) enzyme. These results suggest that Val-67 may be essential for actin-binding, that Phe-114 may be related to the folding of DNase I in reptiles and amphibians, and that Ala-114 may be indispensable for actin-binding in mammals.
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Affiliation(s)
- Junko Fujihara
- Department of Legal Medicine, Shimane University School of Medicine 89-1 Enya, Izumo, Shimane 693-8501, Japan
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Le Roux P, Le Luyer B. Traitements inhales bronchodilatateurs et fluidifiants dans la mucoviscidose. Arch Pediatr 2003; 10 Suppl 2:358s-363s. [PMID: 14671935 DOI: 10.1016/s0929-693x(03)90053-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Poor clearance of airway secretions contributes to the pulmonary disease in cystic fibrosis (CF). Bronchodilator therapy might benefit in CF, but the efficacy is controversial. Effects of mucolytic agents have not been demonstrated conclusively. Only, efficacy of recombinant human deoxyribonuclease (rhDNase) is established with a rapid onset of benefit.
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Affiliation(s)
- P Le Roux
- Centre de ressources et de compétence dans la mucoviscidose, département de pédiatrie, groupe hospitalier, 55 bis, rue Gustave-Flaubert, 76600 Le Havre, France.
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Affiliation(s)
- Martin J Tobin
- Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Route 11N, Hines, Illinois 60141, USA.
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