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A recipe for a good clinical pulmonary surfactant. Biomed J 2022; 45:615-628. [PMID: 35272060 PMCID: PMC9486245 DOI: 10.1016/j.bj.2022.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 12/11/2022] Open
Abstract
The lives of thousands premature babies have been saved along the last thirty years thanks to the establishment and consolidation of pulmonary surfactant replacement therapies (SRT). It took some time to close the gap between the identification of the biophysical and molecular causes of the high mortality associated with respiratory distress syndrome in very premature babies and the development of a proper therapy. Closing the gap required the elucidation of some key questions defining the structure–function relationships in surfactant as well as the particular role of the different molecular components assembled into the surfactant system. On the other hand, the application of SRT as part of treatments targeting other devastating respiratory pathologies, in babies and adults, is depending on further extensive research still required before enough amounts of good humanized clinical surfactants will be available. This review summarizes our current concepts on the compositional and structural determinants defining pulmonary surfactant activity, the principles behind the development of efficient natural animal-derived or recombinant or synthetic therapeutic surfactants, as well as a the most promising lines of research that are already opening new perspectives in the application of tailored surfactant therapies to treat important yet unresolved respiratory pathologies.
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Structural hallmarks of lung surfactant: Lipid-protein interactions, membrane structure and future challenges. Arch Biochem Biophys 2021; 703:108850. [PMID: 33753033 DOI: 10.1016/j.abb.2021.108850] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/20/2021] [Accepted: 03/16/2021] [Indexed: 11/23/2022]
Abstract
Lung surfactant (LS) is an outstanding example of how a highly regulated and dynamic membrane-based system has evolved to sustain a wealth of structural reorganizations in order to accomplish its biophysical function, as it coats and stabilizes the respiratory air-liquid interface in the mammalian lung. The present review dissects the complexity of the structure-function relationships in LS through an updated description of the lipid-protein interactions and the membrane structures that sustain its synthesis, secretion, interfacial performance and recycling. We also revise the current models and the biophysical techniques employed to study the membranous architecture of LS. It is important to consider that the structure and functional properties of LS are often studied in bulk or under static conditions, in spite that surfactant function is strongly connected with a highly dynamic behaviour, sustained by very polymorphic structures and lipid-lipid, lipid-protein and protein-protein interactions that reorganize in precise spatio-temporal coordinates. We have tried to underline the evidences available of the existence of such structural dynamism in LS. A last important aspect is that the synthesis and assembly of LS is a strongly regulated intracellular process to ensure the establishment of the proper interactions driving LS surface activity, while protecting the integrity of other cell membranes. The use of simplified lipid models or partial natural materials purified from animal tissues could be too simplistic to understand the true molecular mechanisms defining surfactant function in vivo. In this line, we will bring into the attention of the reader the methodological challenges and the questions still open to understand the structure-function relationships of LS at its full biological relevance.
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Johansson J, Curstedt T. Synthetic surfactants with SP-B and SP-C analogues to enable worldwide treatment of neonatal respiratory distress syndrome and other lung diseases. J Intern Med 2019; 285:165-186. [PMID: 30357986 DOI: 10.1111/joim.12845] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Treatment of neonatal respiratory distress syndrome (RDS) using animal-derived lung surfactant preparations has reduced the mortality of handling premature infants with RDS to a 50th of that in the 1960s. The supply of animal-derived lung surfactants is limited and only a part of the preterm babies is treated. Thus, there is a need to develop well-defined synthetic replicas based on key components of natural surfactant. A synthetic product that equals natural-derived surfactants would enable cost-efficient production and could also facilitate the development of the treatments of other lung diseases than neonatal RDS. Recently the first synthetic surfactant that contains analogues of the two hydrophobic surfactant proteins B (SP-B) and SP-C entered clinical trials for the treatment of neonatal RDS. The development of functional synthetic analogues of SP-B and SP-C, however, is considerably more challenging than anticipated 30 years ago when the first structural information of the native proteins became available. For SP-B, a complex three-dimensional dimeric structure stabilized by several disulphides has necessitated the design of miniaturized analogues. The main challenge for SP-C has been the pronounced amyloid aggregation propensity of its transmembrane region. The development of a functional non-aggregating SP-C analogue that can be produced synthetically was achieved by designing the amyloidogenic native sequence so that it spontaneously forms a stable transmembrane α-helix.
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Affiliation(s)
- J Johansson
- Department of Neurobiology, Care Sciences and Society, Section for Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - T Curstedt
- Laboratory for Surfactant Research, Department of Molecular Medicine and Surgery, Karolinska Institutet at Karolinska University Hospital, Stockholm, Sweden
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Roldan N, Pérez-Gil J, Morrow MR, García-Álvarez B. Divide & Conquer: Surfactant Protein SP-C and Cholesterol Modulate Phase Segregation in Lung Surfactant. Biophys J 2017; 113:847-859. [PMID: 28834721 PMCID: PMC5567427 DOI: 10.1016/j.bpj.2017.06.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/15/2017] [Accepted: 06/26/2017] [Indexed: 02/04/2023] Open
Abstract
Lung surfactant (LS) is an essential system supporting the respiratory function. Cholesterol can be deleterious for LS function, a condition that is reversed by the presence of the lipopeptide SP-C. In this work, the structure of LS-mimicking membranes has been analyzed under the combined effect of SP-C and cholesterol by deuterium NMR and phosphorus NMR and by electron spin resonance. Our results show that SP-C induces phase segregation at 37°C, resulting in an ordered phase with spectral features resembling an interdigitated state enriched in dipalmitoylphosphatidylcholine, a liquid-crystalline bilayer phase, and an extremely mobile phase consistent with small vesicles or micelles. In the presence of cholesterol, POPC and POPG motion seem to be more hindered by SP-C than dipalmitoylphosphatidylcholine. The use of deuterated cholesterol did not show signs of specific interactions that could be attributed to SP-C or to the other hydrophobic surfactant protein SP-B. Palmitoylation of SP-C had an indirect effect on the extent of protein-lipid perturbations by stabilizing SP-C structure, and seemed to be important to maximize differences among the lipids participating in each phase. These results shed some light on how SP-C-induced lipid perturbations can alter membrane structure to sustain LS functionality at the air-liquid interface.
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Affiliation(s)
- Nuria Roldan
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Healthcare Research Institute of Hospital 12 de Octubre, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Jesús Pérez-Gil
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Healthcare Research Institute of Hospital 12 de Octubre, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Michael R Morrow
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Begoña García-Álvarez
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Healthcare Research Institute of Hospital 12 de Octubre, Hospital Universitario 12 de Octubre, Madrid, Spain.
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Baoukina S, Tieleman DP. Computer simulations of lung surfactant. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2431-2440. [PMID: 26922885 DOI: 10.1016/j.bbamem.2016.02.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/21/2016] [Accepted: 02/23/2016] [Indexed: 01/26/2023]
Abstract
Lung surfactant lines the gas-exchange interface in the lungs and reduces the surface tension, which is necessary for breathing. Lung surfactant consists mainly of lipids with a small amount of proteins and forms a monolayer at the air-water interface connected to bilayer reservoirs. Lung surfactant function involves transfer of material between the monolayer and bilayers during the breathing cycle. Lipids and proteins are organized laterally in the monolayer; selected species are possibly preferentially transferred to bilayers. The complex 3D structure of lung surfactant and the exact roles of lipid organization and proteins remain important goals for research. We review recent simulation studies on the properties of lipid monolayers, monolayers with phase coexistence, monolayer-bilayer transformations, lipid-protein interactions, and effects of nanoparticles on lung surfactant. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Svetlana Baoukina
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - D Peter Tieleman
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
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Roldan N, Goormaghtigh E, Pérez-Gil J, Garcia-Alvarez B. Palmitoylation as a key factor to modulate SP-C–lipid interactions in lung surfactant membrane multilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:184-91. [DOI: 10.1016/j.bbamem.2014.10.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 09/16/2014] [Accepted: 10/01/2014] [Indexed: 11/24/2022]
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Walther FJ, Waring AJ, Hernández-Juviel JM, Ruchala P, Wang Z, Notter RH, Gordon LM. Surfactant protein C peptides with salt-bridges ("ion-locks") promote high surfactant activities by mimicking the α-helix and membrane topography of the native protein. PeerJ 2014; 2:e485. [PMID: 25083348 PMCID: PMC4106191 DOI: 10.7717/peerj.485] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 06/23/2014] [Indexed: 11/20/2022] Open
Abstract
Background. Surfactant protein C (SP-C; 35 residues) in lungs has a cationic N-terminal domain with two cysteines covalently linked to palmitoyls and a C-terminal region enriched in Val, Leu and Ile. Native SP-C shows high surface activity, due to SP-C inserting in the bilayer with its cationic N-terminus binding to the polar headgroup and its hydrophobic C-terminus embedded as a tilted, transmembrane α-helix. The palmitoylcysteines in SP-C act as ‘helical adjuvants’ to maintain activity by overriding the β-sheet propensities of the native sequences. Objective. We studied SP-C peptides lacking palmitoyls, but containing glutamate and lysine at 4-residue intervals, to assess whether SP-C peptides with salt-bridges (“ion-locks”) promote surface activity by mimicking the α-helix and membrane topography of native SP-C. Methods. SP-C mimics were synthesized that reproduce native sequences, but without palmitoyls (i.e., SP-Css or SP-Cff, with serines or phenylalanines replacing the two cysteines). Ion-lock SP-C molecules were prepared by incorporating single or double Glu−–Lys+ into the parent SP-C’s. The secondary structures of SP-C mimics were studied with Fourier transform infrared (FTIR) spectroscopy and PASTA, an algorithm that predicts β-sheet propensities based on the energies of the various β-sheet pairings. The membrane topography of SP-C mimics was investigated with orientated and hydrogen/deuterium (H/D) exchange FTIR, and also Membrane Protein Explorer (MPEx) hydropathy analysis. In vitro surface activity was determined using adsorption surface pressure isotherms and captive bubble surfactometry, and in vivo surface activity from lung function measures in a rabbit model of surfactant deficiency. Results. PASTA calculations predicted that the SP-Css and SP-Cff peptides should each form parallel β-sheet aggregates, with FTIR spectroscopy confirming high parallel β-sheet with ‘amyloid-like’ properties. The enhanced β-sheet properties for SP-Css and SP-Cff are likely responsible for their low surfactant activities in the in vitro and in vivo assays. Although standard 12C-FTIR study showed that the α-helicity of these SP-C sequences in lipids was uniformly increased with Glu−–Lys+ insertions, elevated surfactant activity was only selectively observed. Additional results from oriented and H/D exchange FTIR experiments indicated that the high surfactant activities depend on the SP-C ion-locks recapitulating both the α-helicity and the membrane topography of native SP-C. SP-Css ion-lock 1, an SP-Css with a salt-bridge for a Glu−–Lys+ ion-pair predicted from MPEx hydropathy calculations, demonstrated enhanced surfactant activity and a transmembrane helix simulating those of native SP-C. Conclusion. Highly active SP-C mimics were developed that replace the palmitoyls of SP-C with intrapeptide salt-bridges and represent a new class of synthetic surfactants with therapeutic interest.
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Affiliation(s)
- Frans J Walther
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , United States of America ; Department of Pediatrics, David Geffen School of Medicine, University of California at Los Angeles , Los Angeles, CA , United States of America
| | - Alan J Waring
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , United States of America ; Department of Pediatrics, David Geffen School of Medicine, University of California at Los Angeles , Los Angeles, CA , United States of America ; Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles , Los Angeles, CA , United States of America ; Department of Physiology & Biophysics, School of Medicine, University of California , Irvine, CA , United States of America
| | - José M Hernández-Juviel
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , United States of America
| | - Piotr Ruchala
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles , Los Angeles, CA , United States of America
| | - Zhengdong Wang
- Department of Pediatrics, University of Rochester , Rochester, NY , United States of America
| | - Robert H Notter
- Department of Pediatrics, University of Rochester , Rochester, NY , United States of America
| | - Larry M Gordon
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , United States of America
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Lhor M, Bernier SC, Horchani H, Bussières S, Cantin L, Desbat B, Salesse C. Comparison between the behavior of different hydrophobic peptides allowing membrane anchoring of proteins. Adv Colloid Interface Sci 2014; 207:223-39. [PMID: 24560216 PMCID: PMC4028306 DOI: 10.1016/j.cis.2014.01.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/11/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Membrane binding of proteins such as short chain dehydrogenase reductases or tail-anchored proteins relies on their N- and/or C-terminal hydrophobic transmembrane segment. In this review, we propose guidelines to characterize such hydrophobic peptide segments using spectroscopic and biophysical measurements. The secondary structure content of the C-terminal peptides of retinol dehydrogenase 8, RGS9-1 anchor protein, lecithin retinol acyl transferase, and of the N-terminal peptide of retinol dehydrogenase 11 has been deduced by prediction tools from their primary sequence as well as by using infrared or circular dichroism analyses. Depending on the solvent and the solubilization method, significant structural differences were observed, often involving α-helices. The helical structure of these peptides was found to be consistent with their presumed membrane binding. Langmuir monolayers have been used as membrane models to study lipid-peptide interactions. The values of maximum insertion pressure obtained for all peptides using a monolayer of 1,2-dioleoyl-sn-glycero-3-phospho-ethanolamine (DOPE) are larger than the estimated lateral pressure of membranes, thus suggesting that they bind membranes. Polarization modulation infrared reflection absorption spectroscopy has been used to determine the structure and orientation of these peptides in the absence and in the presence of a DOPE monolayer. This lipid induced an increase or a decrease in the organization of the peptide secondary structure. Further measurements are necessary using other lipids to better understand the membrane interactions of these peptides.
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Affiliation(s)
- Mustapha Lhor
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Sarah C Bernier
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Habib Horchani
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Sylvain Bussières
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Line Cantin
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Bernard Desbat
- CBMN-UMR 5248 CNRS, Université de Bordeaux, IPB, Allée Geoffroy Saint Hilaire, 33600 Pessac, France
| | - Christian Salesse
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada.
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9
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Interaction of Nanoparticles with Lipid Monolayers and Lung Surfactant Films. MEASURING BIOLOGICAL IMPACTS OF NANOMATERIALS 2014. [DOI: 10.1007/11663_2014_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Lu H, Li W, Shao G, Wang H. Expression of SP-C and Ki67 in lungs of preterm infants dying from respiratory distress syndrome. Eur J Histochem 2012; 56:e35. [PMID: 23027351 PMCID: PMC3493981 DOI: 10.4081/ejh.2012.e35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 11/28/2022] Open
Abstract
This study aimed at exploring the expression of Surfactant protein-C (SP-C) and Ki67 in autopsy lung tissues of premature infants dying from respiratory distress syndrome (RDS) who were exposed to mechanical ventilation and elevated oxygen concentrations. The possible influence of pulmonary surfactant (PS) on the expression of SP-C and Ki67 was also investigated. Thirty preterm infants were selected who were histologically and clinically diagnosed as RDS. Preterm infants with RDS were divided into 4 groups, according to the time of death: infants ventilated for 1–3 days, 4–8 days, 9–16 days and >6 days. Five premature infants died within 1 day after delivery for non- pulmonary reasons served as controls. The expression of SP-C and Ki67 in lungs was detected by immunohistochemistry. Compared with the control group, the expression of SP-C and Ki67 in RDS infants decreased significantly after 1–3 days of ventilation, but increased after 4 days and reached peak value after 9–16 days. No significant difference in the expression of SP-C and Ki67 was found between infants treated with PS and those without. Thus our results suggest SP-C and Ki67 may have participated in the pulmonary pathological process in ventilated/oxygen treated preterm infants with RDS, and exogenous surfactant had no effect on the expression of SP-C and Ki67 in the lungs of ventilated/oxygen treated preterm infants with RDS.
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Affiliation(s)
- H Lu
- Department of Pediatrics, Affiliated Hospital of Jiangsu University, Zhenjiang, China
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11
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Bone marrow mesenchymal stem cells can differentiate into type II alveolar epithelial cells in vitro. Cell Biol Int 2012; 35:1261-6. [PMID: 21542803 DOI: 10.1042/cbi20110026] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, we demonstrate that BMSCs (bone marrow mesenchymal stem cells) can be successfully differentiated into type II alveolar epithelial cells in vitro under mimic pulmonary microenvironment. BMSCs were co-cultured with MRC-5 cells in modified SAGM (small airway growth medium). The BMSC-derived type II alveolar epithelial cells morphologically resemble human lung epithelial cells. They began to appear after 10 days in co-culture and became morphologically dominant after day 15. Correspondingly, SPC (surfactant protein C), a specific functional marker of human type II alveolar epithelial cells, was detected in differentiated cells by RT-PCR (reverse transcription-PCR) analysis after day 15. Immunostaining analysis revealed the present of scattered SPC-positive cells with a differentiation efficiency of 2.43-4.21%. Our study further showed that the SPC gene expression level in differentiated cells was related to the ratio of BMSCs to MRC-5 cells and the components of modified SAGM.
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Brown NJ, Dohm MT, Bernardino de la Serna J, Barron AE. Biomimetic N-terminal alkylation of peptoid analogues of surfactant protein C. Biophys J 2011; 101:1076-85. [PMID: 21889444 DOI: 10.1016/j.bpj.2011.04.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 04/11/2011] [Accepted: 04/18/2011] [Indexed: 10/17/2022] Open
Abstract
Surfactant protein C (SP-C) is a hydrophobic lipopeptide that is critical for lung function, in part because it physically catalyzes the formation of surface-associated surfactant reservoirs. Many of SP-C's key biophysical properties derive from its highly stable and hydrophobic α-helix. However, SP-C's posttranslational modification with N-terminal palmitoyl chains also seems to be quite important. We created a new (to our knowledge) class of variants of a synthetic, biomimetic family of peptide mimics (peptoids) that allow us to study the functional effects of biomimetic N-terminal alkylation in vitro. Mimics were designed to emulate the amphipathic patterning, helicity, and hydrophobicity of SP-C, and to include no, one, or two vicinal amide-linked, N-terminal octadecyl chains (providing a reach equivalent to that of natural palmitoyl chains). Pulsating bubble surfactometry and Langmuir-Wilhelmy surface balance studies showed that alkylation improved biomimetic surface activities, yielding lower film compressibility and lower maximum dynamic surface tensions. Atomic force microscopy studies indicated that alkyl chains bind to and retain segregated interfacial surfactant phases at low surface tensions by inducing 3D structural transitions in the monolayer's fluid-like phase, forming surfactant-associated reservoirs. Peptoid-based SP-C mimics are easily produced and purified, and offer much higher chemical and secondary structure stability than polypeptide-based mimics. In surfactant replacements intended for medical use, synthetic SP mimics reduce the odds of pathogen contamination, which may facilitate the wider use of surfactant treatment of respiratory disorders and diseases.
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Affiliation(s)
- Nathan J Brown
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, USA
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Molecular dynamics simulation of phase transitions in model lung surfactant monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2450-65. [DOI: 10.1016/j.bbamem.2011.06.026] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 06/07/2011] [Accepted: 06/08/2011] [Indexed: 01/13/2023]
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Harishchandra RK, Sachan AK, Kerth A, Lentzen G, Neuhaus T, Galla HJ. Compatible solutes: ectoine and hydroxyectoine improve functional nanostructures in artificial lung surfactants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2830-40. [PMID: 21889490 DOI: 10.1016/j.bbamem.2011.08.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 08/05/2011] [Accepted: 08/16/2011] [Indexed: 11/25/2022]
Abstract
Ectoine and hydroxyectoine belong to the family of compatible solutes and are among the most abundant osmolytes in nature. These compatible solutes protect biomolecules from extreme conditions and maintain their native function. In the present study, we have investigated the effect of ectoine and hydroxyectoine on the domain structures of artificial lung surfactant films consisting of dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG) and the lung surfactant specific surfactant protein C (SP-C) in a molar ratio of 80:20:0.4. The pressure-area isotherms are found to be almost unchanged by both compatible solutes. The topology of the fluid domains shown by scanning force microscopy, which is thought to be responsible for the biophysical behavior under compression, however, is modified giving rise to the assumption that ectoine and hydroxyectoine are favorable for a proper lung surfactant function. This is further evidenced by the analysis of the insertion kinetics of lipid vesicles into the lipid-peptide monolayer, which is clearly enhanced in the presence of both compatible solutes. Thus, we could show that ectoine and hydroxyectoine enhance the function of lung surfactant in a simple model system, which might provide an additional rationale to inhalative therapy.
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Affiliation(s)
- Rakesh Kumar Harishchandra
- Institute of Biochemistry, Westfälische Wilhelms Universität, Wilhelm Klemm Str. 2, 48149 Münster, Germany
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Investigating the effect of a single glycine to alanine substitution on interactions of antimicrobial peptide latarcin 2a with a lipid membrane. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:1087-100. [DOI: 10.1007/s00249-011-0726-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/03/2011] [Accepted: 06/12/2011] [Indexed: 10/18/2022]
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16
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Hane F, Drolle E, Leonenko Z. Effect of cholesterol and amyloid-β peptide on structure and function of mixed-lipid films and pulmonary surfactant BLES: an atomic force microscopy study. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2010; 6:808-14. [DOI: 10.1016/j.nano.2010.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 04/22/2010] [Accepted: 05/03/2010] [Indexed: 10/19/2022]
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Duncan SL, Larson RG. Folding of lipid monolayers containing lung surfactant proteins SP-B1–25 and SP-C studied via coarse-grained molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1632-50. [DOI: 10.1016/j.bbamem.2010.04.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 04/05/2010] [Accepted: 04/08/2010] [Indexed: 12/31/2022]
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Dohm MT, Brown NJ, Seurynck-Servoss SL, de la Serna JB, Barron AE. Mimicking SP-C palmitoylation on a peptoid-based SP-B analogue markedly improves surface activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1663-78. [DOI: 10.1016/j.bbamem.2010.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 04/20/2010] [Accepted: 04/26/2010] [Indexed: 02/01/2023]
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Yassine W, Milochau A, Buchoux S, Lang J, Desbat B, Oda R. Effect of monolayer lipid charges on the structure and orientation of protein VAMP1 at the air–water interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:928-37. [DOI: 10.1016/j.bbamem.2010.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 12/02/2009] [Accepted: 01/13/2010] [Indexed: 12/20/2022]
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Ravasio A, Cruz A, Pérez-Gil J, Haller T. High-throughput evaluation of pulmonary surfactant adsorption and surface film formation. J Lipid Res 2008; 49:2479-88. [DOI: 10.1194/jlr.d800029-jlr200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Abstract
Since the widespread use of exogenous lung surfactant to treat neonatal respiratory distress syndrome, premature infant survival and respiratory morbidity have dramatically improved. Despite the effectiveness of the animal-derived surfactant preparations, there still remain some concerns and difficulties associated with their use. This has prompted investigation into the creation of synthetic surfactant preparations. However, to date, no clinically used synthetic formulation is as effective as the natural material. This is largely because the previous synthetic formulations lacked analogues of the hydrophobic proteins of the lung surfactant system, SP-B and SP-C, which are critical functional constituents. As a result, recent investigation has turned toward the development of a new generation of synthetic, biomimetic surfactants that contain synthetic phospholipids along with a mimic of the hydrophobic protein portion of lung surfactant. In this Account, we detail our efforts in creating accurate mimics of SP-C for use in a synthetic surfactant replacement therapy. Despite SP-C's seemingly simple structure, the predominantly helical protein is extraordinarily challenging to work with given its extreme hydrophobicity and structural instability, which greatly complicates the creation of an effective SP-C analogue. Drawing inspiration from Nature, two promising biomimetic approaches have led to the creation of rationally designed biopolymers that recapitulate many of SP-C's molecular features. The first approach utilizes detailed SP-C structure-activity relationships and amino acid folding propensities to create a peptide-based analogue, SP-C33. In SP-C33, the problematic and metastable polyvaline helix is replaced with a structurally stable polyleucine helix and includes a well-placed positive charge to prevent aggregation. SP-C33 is structurally stable and eliminates the association propensity of the native protein. The second approach follows the same design considerations but makes use of a non-natural, poly-N-substituted glycine or "peptoid" scaffold to circumvent the difficulties associated with SP-C. By incorporating unique biomimetic side chains in a non-natural backbone, the peptoid mimic captures both SP-C's hydrophobic patterning and its helical secondary structure. Despite the differences in structure, both SP-C33 and the SP-C peptoid mimic capture many requisite features of SP-C. In a surfactant environment, these analogues also replicate many of the key surface activities necessary for a functional biomimetic surfactant therapy while overcoming the difficulties associated with the natural protein. With improved stability, greater production potential, and elimination of possible pathogenic contamination, these biomimetic surfactant formulations offer not only the potential to improve the treatment of respiratory distress syndrome but also the opportunity to treat other respiratory-related disorders.
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Affiliation(s)
- Nathan J. Brown
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
| | - Jan Johansson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, SE-751 23 Uppsala, Sweden
| | - Annelise E. Barron
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
- Department of Bioengineering, Stanford University, 318 Campus Drive, Stanford, California 94305
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Plasencia I, Baumgart F, Andreu D, Marsh D, Pérez-Gil J. Effect of acylation on the interaction of the N-Terminal segment of pulmonary surfactant protein SP-C with phospholipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1274-82. [DOI: 10.1016/j.bbamem.2008.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 01/22/2008] [Accepted: 02/07/2008] [Indexed: 02/02/2023]
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Saleem M, Meyer MC, Breitenstein D, Galla HJ. The Surfactant Peptide KL4 in Lipid Monolayers. J Biol Chem 2008; 283:5195-207. [DOI: 10.1074/jbc.m705944200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Brown NJ, Wu CW, Seurynck-Servoss SL, Barron AE. Effects of Hydrophobic Helix Length and Side Chain Chemistry on Biomimicry in Peptoid Analogues of SP-C. Biochemistry 2008; 47:1808-18. [PMID: 18197709 DOI: 10.1021/bi7021975] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nathan J. Brown
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, and Department of Bioengineering, Stanford University, 318 Campus Drive, Stanford, California 94305
| | - Cindy W. Wu
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, and Department of Bioengineering, Stanford University, 318 Campus Drive, Stanford, California 94305
| | - Shannon L. Seurynck-Servoss
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, and Department of Bioengineering, Stanford University, 318 Campus Drive, Stanford, California 94305
| | - Annelise E. Barron
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, and Department of Bioengineering, Stanford University, 318 Campus Drive, Stanford, California 94305
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