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Abstract
Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.
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Affiliation(s)
- Fred Possmayer
- Department of Biochemistry, Western University, London, Ontario N6A 3K7, Canada
- Department of Obstetrics/Gynaecology, Western University, London, Ontario N6A 3K7, Canada
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manon, Honolulu, Hawaii 96822, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96826, United States
| | - Ruud A W Veldhuizen
- Department of Physiology & Pharmacology, Western University, London, Ontario N6A 5C1, Canada
- Department of Medicine, Western University, London, Ontario N6A 3K7, Canada
- Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Nils O Petersen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Western University, London, Ontario N6A 5B7, Canada
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2
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Garavaglia ML, Bodega F, Porta C, Milzani A, Sironi C, Dalle-Donne I. Molecular Impact of Conventional and Electronic Cigarettes on Pulmonary Surfactant. Int J Mol Sci 2023; 24:11702. [PMID: 37511463 PMCID: PMC10380520 DOI: 10.3390/ijms241411702] [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: 06/20/2023] [Revised: 07/11/2023] [Accepted: 07/15/2023] [Indexed: 07/30/2023] Open
Abstract
The alveolar epithelium is covered by a non-cellular layer consisting of an aqueous hypophase topped by pulmonary surfactant, a lipo-protein mixture with surface-active properties. Exposure to cigarette smoke (CS) affects lung physiology and is linked to the development of several diseases. The macroscopic effects of CS are determined by several types of cell and molecular dysfunction, which, among other consequences, lead to surfactant alterations. The purpose of this review is to summarize the published studies aimed at uncovering the effects of CS on both the lipid and protein constituents of surfactant, discussing the molecular mechanisms involved in surfactant homeostasis that are altered by CS. Although surfactant homeostasis has been the topic of several studies and some molecular pathways can be deduced from an analysis of the literature, it remains evident that many aspects of the mechanisms of action of CS on surfactant homeostasis deserve further investigation.
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Affiliation(s)
| | - Francesca Bodega
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, 20133 Milan, Italy
| | - Cristina Porta
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, 20133 Milan, Italy
| | - Aldo Milzani
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy
| | - Chiara Sironi
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, 20133 Milan, Italy
| | - Isabella Dalle-Donne
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy
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3
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Blanco FG, Vázquez R, Hernández-Arriaga AM, García P, Prieto MA. Enzybiotic-mediated antimicrobial functionalization of polyhydroxyalkanoates. Front Bioeng Biotechnol 2023; 11:1220336. [PMID: 37449090 PMCID: PMC10336440 DOI: 10.3389/fbioe.2023.1220336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023] Open
Abstract
Polymeric nanoparticles (NPs) present some ideal properties as biomedical nanocarriers for targeted drug delivery such as enhanced translocation through body barriers. Biopolymers, such as polyhydroxyalkanoates (PHAs) are gaining attention as nanocarrier biomaterials due to their inherent biocompatibility, biodegradability, and ability to be vehiculized through hydrophobic media, such as the lung surfactant (LS). Upon colonization of the lung alveoli, below the LS layer, Streptococcus pneumoniae, causes community-acquired pneumonia, a severe respiratory condition. In this work, we convert PHA NPs into an antimicrobial material by the immobilization of an enzybiotic, an antimicrobial enzyme, via a minimal PHA affinity tag. We first produced the fusion protein M711, comprising the minimized PHA affinity tag, MinP, and the enzybiotic Cpl-711, which specifically targets S. pneumoniae. Then, a PHA nanoparticulate suspension with adequate physicochemical properties for pulmonary delivery was formulated, and NPs were decorated with M711. Finally, we assessed the antipneumococcal activity of the nanosystem against planktonic and biofilm forms of S. pneumoniae. The resulting system displayed sustained antimicrobial activity against both, free and sessile cells, confirming that tag-mediated immobilization of enzybiotics on PHAs is a promising platform for bioactive antimicrobial functionalization.
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Affiliation(s)
- Francisco G. Blanco
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Margarita Salas Center for Biological Research (CIB–CSIC), Madrid, Spain
- Interdisciplinary Platform of Sustainable Plastics towards a Circular Economy, Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Roberto Vázquez
- Protein Engineering Against Antibiotic Resistance Group, Microbial and Plant Biotechnology Department, Margarita Salas Center for Biological Research (CIB-CSIC), Madrid, Spain
| | - Ana M. Hernández-Arriaga
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Margarita Salas Center for Biological Research (CIB–CSIC), Madrid, Spain
- Interdisciplinary Platform of Sustainable Plastics towards a Circular Economy, Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Pedro García
- Protein Engineering Against Antibiotic Resistance Group, Microbial and Plant Biotechnology Department, Margarita Salas Center for Biological Research (CIB-CSIC), Madrid, Spain
| | - M. Auxiliadora Prieto
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Margarita Salas Center for Biological Research (CIB–CSIC), Madrid, Spain
- Interdisciplinary Platform of Sustainable Plastics towards a Circular Economy, Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
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4
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Liekkinen J, Olżyńska A, Cwiklik L, Bernardino de la Serna J, Vattulainen I, Javanainen M. Surfactant Proteins SP-B and SP-C in Pulmonary Surfactant Monolayers: Physical Properties Controlled by Specific Protein-Lipid Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4338-4350. [PMID: 36917773 PMCID: PMC10061932 DOI: 10.1021/acs.langmuir.2c03349] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The lining of the alveoli is covered by pulmonary surfactant, a complex mixture of surface-active lipids and proteins that enables efficient gas exchange between inhaled air and the circulation. Despite decades of advancements in the study of the pulmonary surfactant, the molecular scale behavior of the surfactant and the inherent role of the number of different lipids and proteins in surfactant behavior are not fully understood. The most important proteins in this complex system are the surfactant proteins SP-B and SP-C. Given this, in this work we performed nonequilibrium all-atom molecular dynamics simulations to study the interplay of SP-B and SP-C with multicomponent lipid monolayers mimicking the pulmonary surfactant in composition. The simulations were complemented by z-scan fluorescence correlation spectroscopy and atomic force microscopy measurements. Our state-of-the-art simulation model reproduces experimental pressure-area isotherms and lateral diffusion coefficients. In agreement with previous research, the inclusion of either SP-B and SP-C increases surface pressure, and our simulations provide a molecular scale explanation for this effect: The proteins display preferential lipid interactions with phosphatidylglycerol, they reside predominantly in the lipid acyl chain region, and they partition into the liquid expanded phase or even induce it in an otherwise packed monolayer. The latter effect is also visible in our atomic force microscopy images. The research done contributes to a better understanding of the roles of specific lipids and proteins in surfactant function, thus helping to develop better synthetic products for surfactant replacement therapy used in the treatment of many fatal lung-related injuries and diseases.
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Affiliation(s)
- Juho Liekkinen
- Department
of Physics, University of Helsinki, FI-00560 Helsinki, Finland
| | - Agnieszka Olżyńska
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of
Sciences, CZ-18223 Prague, Czech Republic
| | - Lukasz Cwiklik
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of
Sciences, CZ-18223 Prague, Czech Republic
| | - Jorge Bernardino de la Serna
- National
Heart and Lung Institute, Imperial College
London, Sir Alexander Fleming Building, London SW7 2AZ, U.K.
- NIHR
Imperial Biomedical Research Centre, London SW7 2AZ, U.K.
| | - Ilpo Vattulainen
- Department
of Physics, University of Helsinki, FI-00560 Helsinki, Finland
| | - Matti Javanainen
- Institute
of Biotechnology, University of Helsinki, FI-00790 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, CZ-16100 Prague 6, Czech Republic
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5
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Fluid Films as Models for Understanding the Impact of Inhaled Particles in Lung Surfactant Layers. COATINGS 2022. [DOI: 10.3390/coatings12020277] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Pollution is currently a public health problem associated with different cardiovascular and respiratory diseases. These are commonly originated as a result of the pollutant transport to the alveolar cavity after their inhalation. Once pollutants enter the alveolar cavity, they are deposited on the lung surfactant (LS) film, altering their mechanical performance which increases the respiratory work and can induce a premature alveolar collapse. Furthermore, the interactions of pollutants with LS can induce the formation of an LS corona decorating the pollutant surface, favoring their penetration into the bloodstream and distribution along different organs. Therefore, it is necessary to understand the most fundamental aspects of the interaction of particulate pollutants with LS to mitigate their effects, and design therapeutic strategies. However, the use of animal models is often invasive, and requires a careful examination of different bioethics aspects. This makes it necessary to design in vitro models mimicking some physico-chemical aspects with relevance for LS performance, which can be done by exploiting the tools provided by the science and technology of interfaces to shed light on the most fundamental physico-chemical bases governing the interaction between LS and particulate matter. This review provides an updated perspective of the use of fluid films of LS models for shedding light on the potential impact of particulate matter in the performance of LS film. It should be noted that even though the used model systems cannot account for some physiological aspects, it is expected that the information contained in this review can contribute on the understanding of the potential toxicological effects of air pollution.
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6
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Gao Y, Zhang Z, Wang Y, Zhou D, Zhang J, Chen X, Li X, Shao Q. Impacts of lipopolysaccharide on fetal lung developmental maturity and surfactant protein B and surfactant protein C protein expression in gestational diabetes mellitus rats. Bioengineered 2022; 13:834-843. [PMID: 34898355 PMCID: PMC8805987 DOI: 10.1080/21655979.2021.2013099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/26/2021] [Indexed: 11/25/2022] Open
Abstract
The rise of bioinformatics based on computer medicine provides a new method to reveal the complex biological data. This experiment is to explore the impacts of lipopolysaccharide on fetal lung developmental maturity and expressions of lung surfactant protein B (SP-B) and lung surfactant protein C (SP-C) in rats with gestational diabetes mellitus (GDM), thereby discussing the mechanism of developmental disorders in rats. Forty-eight conceived female rats were experimental subjects. Twenty-eight rats were randomly selected to construct the GDM models. All conceived rats underwent section on the 21st day of pregnancy. The ultrastructure of alveolar type II epithelial cells and the morphology of lung tissue were observed under a microscope. The protein localization and expression of SP-B and SP-C were determined by immunohistochemistry; the protein levels of SP-B and SP-C were determined by Western blot. Blood glucose and body weight of the GDM group were higher than those of the control group; the number of alveoli and alveolar area in the GDM group was lower than those in the control group; the alveolar interval in the GDM group was significantly higher than that in the control group (P < 0.05). The average absorbance of SP-B and SP-C in fetal lung tissue was significantly lower in the GDM group than that in the control group (P < 0.01). Changes in fetal lung tissue structure of rats were related to SP-B and SP-C, which was one of the main factors that affected the maturation of fetal lung tissue.
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Affiliation(s)
- Yue Gao
- Department of Neonatal, The Fourth Hospital of Harbin Medical University, Harbin
| | - Ziwei Zhang
- Public Affairs Management, Medical University of Tianjin, Tianjin, China
| | - Yan Wang
- Rehabilitation Center, The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
| | - Dayong Zhou
- Children’s Rehabilitation Center, Heilongjiang Seamen General Hospital, Harbin, China
| | - Jinghua Zhang
- Department of Health Care, Harbin City Maternal and Child Health Care Family Planning Service Center, Harbin, China
| | - Xiaoyu Chen
- Department of Neonatal, The Fourth Hospital of Harbin Medical University, Harbin
| | - Xin Li
- Department of Neonatal, The Fourth Hospital of Harbin Medical University, Harbin
| | - Qingliang Shao
- Department of Neonatal, The Fourth Hospital of Harbin Medical University, Harbin
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7
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Basabe-Burgos O, Landreh M, Rising A, Curstedt T, Jan Johansson. Treatment of Respiratory Distress Syndrome with Single Recombinant Polypeptides that Combine Features of SP-B and SP-C. ACS Chem Biol 2021; 16:2864-2873. [PMID: 34878249 DOI: 10.1021/acschembio.1c00816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Treatment of respiratory distress syndrome (RDS) with surfactant replacement therapy in prematurely born infants was introduced more than 30 years ago; however, the surfactant preparations currently in clinical use are extracts from animal lungs. A synthetic surfactant that matches the currently used nature-derived surfactant preparations and can be produced in a cost-efficient manner would enable worldwide treatment of neonatal RDS and could also be tested against lung diseases in adults. The major challenge in developing fully functional synthetic surfactant preparations is to recapitulate the properties of the hydrophobic lung surfactant proteins B (SP-B) and SP-C. Here, we have designed single polypeptides that combine properties of SP-B and SP-C and produced them recombinantly using a novel solubility tag based on spider silk production. These Combo peptides mixed with phospholipids are as efficient as nature-derived surfactant preparations against neonatal RDS in premature rabbit fetuses.
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Affiliation(s)
- Oihana Basabe-Burgos
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, 141 83 Huddinge, Sweden
| | - Michael Landreh
- Science for Life Laboratory, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Tomtebodavägen 23A, SE-171 65 Stockholm, Sweden
| | - Anna Rising
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, 141 83 Huddinge, Sweden
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, 751 23 Uppsala, Sweden
| | - Tore Curstedt
- Department of Molecular Medicine and Surgery, Karolinska Institutet at Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Jan Johansson
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, 141 83 Huddinge, Sweden
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8
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Herman L, De Smedt SC, Raemdonck K. Pulmonary surfactant as a versatile biomaterial to fight COVID-19. J Control Release 2021; 342:170-188. [PMID: 34813878 PMCID: PMC8605818 DOI: 10.1016/j.jconrel.2021.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 02/06/2023]
Abstract
The COVID-19 pandemic has wielded an enormous pressure on global health care systems, economics and politics. Ongoing vaccination campaigns effectively attenuate viral spreading, leading to a reduction of infected individuals, hospitalizations and mortality. Nevertheless, the development of safe and effective vaccines as well as their global deployment is time-consuming and challenging. In addition, such preventive measures have no effect on already infected individuals and can show reduced efficacy against SARS-CoV-2 variants that escape vaccine-induced host immune responses. Therefore, it is crucial to continue the development of specific COVID-19 targeting therapeutics, including small molecular drugs, antibodies and nucleic acids. However, despite clear advantages of local drug delivery to the lung, inhalation therapy of such antivirals remains difficult. This review aims to highlight the potential of pulmonary surfactant (PS) in the treatment of COVID-19. Since SARS-CoV-2 infection can progress to COVID-19-related acute respiratory distress syndrome (CARDS), which is associated with PS deficiency and inflammation, replacement therapy with exogenous surfactant can be considered to counter lung dysfunction. In addition, due to its surface-active properties and membrane-interaction potential, PS can be repurposed to enhance drug spreading along the respiratory epithelium and to promote intracellular drug delivery. By merging these beneficial features, PS can be regarded as a versatile biomaterial to combat respiratory infections, in particular COVID-19.
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Affiliation(s)
- Lore Herman
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Stefaan C De Smedt
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Koen Raemdonck
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
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9
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Angles G, Hail A, Dotson RJ, Pias SC. Atomistic simulations modify interpretation of spin-label oximetry data. Part 1: intensified water-lipid interfacial resistances. APPLIED MAGNETIC RESONANCE 2021; 52:1261-1289. [PMID: 37292189 PMCID: PMC10249954 DOI: 10.1007/s00723-021-01398-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 06/10/2023]
Abstract
The role of membrane cholesterol in cellular function and dysfunction has been the subject of much inquiry. A few studies have suggested that cholesterol may slow oxygen diffusive transport, altering membrane physical properties and reducing oxygen permeability. The primary experimental technique used in recent years to study membrane oxygen transport is saturation-recovery electron paramagnetic resonance (EPR) oximetry, using spin-label probes targeted to specific regions of a lipid bilayer. The technique has been used, in particular, to assess the influence of cholesterol on oxygen transport and membrane permeability. The reliability of such EPR recordings at the water-lipid interface near the phospholipid headgroups has been challenged by all-atom molecular dynamics (MD) simulation data that show substantive agreement with spin-label probe measurements throughout much of the bilayer. This work uses further MD simulations, with an updated oxygen model, to determine the location of the maximum resistance to permeation and the rate-limiting barrier to oxygen permeation in 1-palmitoyl,2-oleoylphosphatidylcholine (POPC) and POPC/cholesterol bilayers at 25 and 35°C. The current simulations show a spike of resistance to permeation in the headgroup region that was not detected by EPR but was predicted in early theoretical work by Diamond and Katz. Published experimental nuclear magnetic resonance (NMR) oxygen measurements provide key validation of the MD models and indicate that the positions and relative magnitudes of the phosphatidylcholine resistance peaks are accurate. Consideration of the headgroup-region resistances predicts bilayer permeability coefficients lower than estimated in EPR studies, giving permeabilities lower than the permeability of unstirred water layers of the same thickness. Here, the permeability of POPC at 35°C is estimated to be 13 cm/s, compared with 10 cm/s for POPC/cholesterol and 118 cm/s for simulation water layers of similar thickness. The value for POPC is 12 times lower than estimated from EPR measurements, while the value for POPC/cholesterol is 5 times lower. These findings underscore the value of atomic resolution models for guiding the interpretation of experimental probe-based measurements.
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Affiliation(s)
| | | | | | - Sally C. Pias
- Corresponding author: , Department of Chemistry, New Mexico Institute of Mining and Technology (New Mexico Tech), 801 Leroy Place, Socorro, NM 87801, USA
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10
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Guagliardo R, Herman L, Penders J, Zamborlin A, De Keersmaecker H, Van de Vyver T, Verstraeten S, Merckx P, Mingeot-Leclercq MP, Echaide M, Pérez-Gil J, Stevens MM, De Smedt SC, Raemdonck K. Surfactant Protein B Promotes Cytosolic SiRNA Delivery by Adopting a Virus-like Mechanism of Action. ACS NANO 2021; 15:8095-8109. [PMID: 33724778 DOI: 10.1021/acsnano.0c04489] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
RNA therapeutics are poised to revolutionize medicine. To unlock the full potential of RNA drugs, safe and efficient (nano)formulations to deliver them inside target cells are required. Endosomal sequestration of nanocarriers represents a major bottleneck in nucleic acid delivery. Gaining more detailed information on the intracellular behavior of RNA nanocarriers is crucial to rationally develop delivery systems with improved therapeutic efficiency. Surfactant protein B (SP-B) is a key component of pulmonary surfactant (PS), essential for mammalian breathing. In contrast to the general belief that PS should be regarded as a barrier for inhaled nanomedicines, we recently discovered the ability of SP-B to promote gene silencing by siRNA-loaded and lipid-coated nanogels. However, the mechanisms governing this process are poorly understood. The major objective of this work was to obtain mechanistic insights into the SP-B-mediated cellular delivery of siRNA. To this end, we combined siRNA knockdown experiments, confocal microscopy, and focused ion beam scanning electron microscopy imaging in an in vitro non-small-cell lung carcinoma model with lipid mixing assays on vesicles that mimic the composition of (intra)cellular membranes. Our work highlights a strong correlation between SP-B-mediated fusion with anionic endosomal membranes and cytosolic siRNA delivery, a mode of action resembling that of certain viruses and virus-derived cell-penetrating peptides. Building on these gained insights, we optimized the SP-B proteolipid composition, which dramatically improved delivery efficiency. Altogether, our work provides a mechanistic understanding of SP-B-induced perturbation of intracellular membranes, offering opportunities to fuel the rational design of SP-B-inspired RNA nanoformulations for inhalation therapy.
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Affiliation(s)
- Roberta Guagliardo
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Lore Herman
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Jelle Penders
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Agata Zamborlin
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Herlinde De Keersmaecker
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
- Centre for Advanced Light Microscopy, Ghent University, 9000 Ghent, Belgium
| | - Thijs Van de Vyver
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Sandrine Verstraeten
- Université Catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium
| | - Pieterjan Merckx
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Marie-Paule Mingeot-Leclercq
- Université Catholique de Louvain, Louvain Drug Research Institute, Pharmacologie Cellulaire et Moléculaire, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium
| | - Mercedes Echaide
- Departamento de Bioquímica y Biología Molecular, Facultad de Biologia, and Research Institute Hospital 12 de Octubre, Universidad Complutense, José Antonio Novais 12, 28040 Madrid, Spain
| | - Jesús Pérez-Gil
- Departamento de Bioquímica y Biología Molecular, Facultad de Biologia, and Research Institute Hospital 12 de Octubre, Universidad Complutense, José Antonio Novais 12, 28040 Madrid, Spain
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Stefaan C De Smedt
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Koen Raemdonck
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
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11
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Loney RW, Brandner B, Dagan MP, Smith PN, Roche M, Fritz JR, Hall SB, Tristram-Nagle SA. Changes in membrane elasticity caused by the hydrophobic surfactant proteins correlate poorly with adsorption of lipid vesicles. SOFT MATTER 2021; 17:3358-3366. [PMID: 33630985 PMCID: PMC8016726 DOI: 10.1039/d0sm02223c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
To establish how the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of lipids to an air/water interface, we used X-ray diffuse scattering (XDS) to determine an order parameter of the lipid chains (Sxray) and the bending modulus of the lipid bilayers (KC). Samples contained different amounts of the proteins with two sets of lipids. Dioleoylphosphatidylcholine (DOPC) provided a simple, well characterized model system. The nonpolar and phospholipids (N&PL) from extracted calf surfactant provided the biological mix of lipids. For both systems, the proteins produced changes in Sxray that correlated well with KC. The dose-response to the proteins, however, differed. Small amounts of protein generated large decreases in Sxray and KC for DOPC that progressed monotonically. The changes for the surfactant lipids were erratic. Our studies then tested whether the proteins produced correlated effects on adsorption. Experiments measured the initial fall in surface tension during adsorption to a constant surface area, and then expansion of the interface during adsorption at a constant surface tension of 40 mN m-1. The proteins produced a sigmoidal increase in the rate of adsorption at 40 mN m-1 for both lipids. The results correlated poorly with the changes in Sxray and KC in both cases. Disordering of the lipid chains produced by the proteins, and the softening of the bilayers, fail to explain how the proteins promote adsorption of lipid vesicles.
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Affiliation(s)
- Ryan W Loney
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, USA.
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12
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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: 28] [Impact Index Per Article: 9.3] [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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Tang YS, Zhang XJ, Wang WN, Wang T, Cao WL, Zhang QH, Chen F. Fusion Expression and Fibrinolytic Activity of rPA/SP-B. Protein Pept Lett 2021; 28:1033-1042. [PMID: 33645472 DOI: 10.2174/0929866528666210301151302] [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: 10/08/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Pulmonary surfactant dysfunction is an important pathological factor in acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF). OBJECTIVE In this study, the characteristics of recombinant mature surfactant protein B (SP-B) and reteplase (rPA) fusion protein maintaining good pulmonary surface activity and rPA fibrinolytic activity in acute lung injury cell model were studied. METHODS We studied the characteristics of SP-B fusion expression, cloned rPA gene and N-terminal rPA/C-terminal SP-B co-expression gene, and constructed them into eukaryotic expression vector pEZ-M03 to obtain recombinant plasmids pEZ-rPA and pEZ-rPA/SP-B. The recombinant plasmids was transfected into Chinese hamster ovary (CHO) K1 cells and the expression products were analyzed by Western Blot. Lipopolysaccharide (LPS) was used to induce CCL149 (an alveolar epithelial cell line) cell injury model. Fluorescence staining of rPA and rPA/SP-B was carried out with the enhanced green fluorescent protein (eGFP) that comes with pEZ-M03; the cell Raman spectroscopy technique was used to analyze the interaction between rPA/SP-B fusion protein and the phospholipid structure of cell membrane in CCL149 cells. The enzyme activity of rPA in the fusion protein was determined by fibrin-agarose plate method. RESULTS The rPA/SP-B fusion protein was successfully expressed. In the CCL149 cell model of acute lung injury (ALI), the green fluorescence of rPA/SP-B is mainly distributed on the CCL149 cell membrane. The rPA/SP-B fusion protein can reduce the disorder of phospholipid molecules and reduce cell membrane damage. The enzyme activity of rPA/SP-B fusion protein was 3.42, and the fusion protein still had good enzyme activity. CONCLUSION The recombinant eukaryotic plasmid pEZ-rPA/SP-B is constructed and can be expressed in the eukaryotic system. Studies have shown that rPA/SP-B fusion protein maintains good SP-B lung surface activity and rPA enzyme activity in acute lung injury cell model.
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Affiliation(s)
- Yi-Shan Tang
- Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Bioengineering, Chongqing University of Technology, Bananqu, Chongqing 400054, China
| | - Xiao-Jun Zhang
- Molecular Pathology Lab, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Wan-Neng Wang
- Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Bioengineering, Chongqing University of Technology, Bananqu, Chongqing 400054, China
| | - Ting Wang
- Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Bioengineering, Chongqing University of Technology, Bananqu, Chongqing 400054, China
| | - Wu-Long Cao
- Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Bioengineering, Chongqing University of Technology, Bananqu, Chongqing 400054, China
| | - Qiu-Han Zhang
- Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Bioengineering, Chongqing University of Technology, Bananqu, Chongqing 400054, China
| | - Fu Chen
- Department of Microbiology and Biochemical Pharmacy, College of Pharmacy and Bioengineering, Chongqing University of Technology, Bananqu, Chongqing 400054, China
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Martínez-Calle M, Parra-Ortiz E, Cruz A, Olmeda B, Pérez-Gil J. Towards the Molecular Mechanism of Pulmonary Surfactant Protein SP-B: At the Crossroad of Membrane Permeability and Interfacial Lipid Transfer. J Mol Biol 2020; 433:166749. [PMID: 33309854 DOI: 10.1016/j.jmb.2020.166749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/14/2020] [Accepted: 12/03/2020] [Indexed: 11/17/2022]
Abstract
Pulmonary surfactant is a lipid-protein complex that coats the alveolar air-liquid interface, enabling the proper functioning of lung mechanics. The hydrophobic surfactant protein SP-B, in particular, plays an indispensable role in promoting the rapid adsorption of phospholipids into the interface. For this, formation of SP-B ring-shaped assemblies seems to be important, as oligomerization could be required for the ability of the protein to generate membrane contacts and to mediate lipid transfer among surfactant structures. SP-B, together with the other hydrophobic surfactant protein SP-C, also promotes permeability of surfactant membranes to polar molecules although the molecular mechanisms underlying this property, as well as its relevance for the surface activity of the protein, remain undefined. In this work, the contribution of SP-B and SP-C to surfactant membrane permeability has been further investigated, by evaluation of the ability of differently-sized fluorescent polar probes to permeate through giant vesicles with different lipid/protein composition. Our results are consistent with the generation by SP-B of pores with defined size in surfactant membranes. Furthermore, incubation of surfactant with an anti-SP-B antibody not only blocked membrane permeability but also affected lipid transfer into the air-water interface, as observed in a captive bubble surfactometer device. Our findings include the identification of SP-C and anionic phospholipids as modulators required for maintaining native-like permeability features in pulmonary surfactant membranes. Proper permeability through membrane assemblies could be crucial to complement the overall role of surfactant in maintaining alveolar equilibrium, beyond its biophysical function in stabilizing the respiratory air-liquid interface.
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Affiliation(s)
- Marta Martínez-Calle
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Research Institute "Hospital 12 de Octubre (imas12)", Complutense University, Madrid, Spain
| | - Elisa Parra-Ortiz
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain
| | - Antonio Cruz
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Research Institute "Hospital 12 de Octubre (imas12)", Complutense University, Madrid, Spain
| | - Barbara Olmeda
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Research Institute "Hospital 12 de Octubre (imas12)", Complutense University, Madrid, Spain.
| | - Jesús Pérez-Gil
- Department of Biochemistry, Faculty of Biology, Complutense University, Madrid, Spain; Research Institute "Hospital 12 de Octubre (imas12)", Complutense University, Madrid, Spain
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Oseliero Filho PL, Gerbelli BB, Fornasier F, Chaves Filho AB, Yoshinaga MY, Miyamoto S, Mortara L, Lacerda CD, Cuccovia IM, Pimentel AS, Oliveira CLP. Structure and Thermotropic Behavior of Bovine- and Porcine-Derived Exogenous Lung Surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:14514-14529. [PMID: 33210931 DOI: 10.1021/acs.langmuir.0c02224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two commercial exogenous pulmonary surfactants, Curosurf and Survanta, are investigated. Their thermotropic behavior and associated structural changes for the samples in bulk are characterized and described. For Survanta, the obtained results of differential scanning calorimetry showed a thermogram with three peaks on heating and only a single peak on cooling. Curosurf on the other hand, presents calorimetric thermograms with only one peak in both the heating and cooling scans. This distinct thermotropic behavior between the two pulmonary surfactants, a consequence of their particular compositions, is associated with structural changes that were evaluated by simultaneous small- and wide-angle X-ray scattering experiments with in situ temperature variation. Interestingly, for temperatures below ∼35 °C for Curosurf and ∼53 °C for Survanta, the scattering data indicated the coexistence of two lamellar phases with different carbon chain organizations. For temperatures above these limits, the coexistence of phases disappears, giving rise to a fluid phase in both pulmonary surfactants, with multilamelar vesicles for Curosurf and unilamellar vesicles for Survanta. This process is quasi-reversible under cooling, and advanced data analysis for the scattering data indicated differences in the structural and elastic properties of the pulmonary surfactants. The detailed and systematic investigation shown in this work expands on the knowledge of the structure and thermodynamic behavior of Curosurf and Survanta, being relevant from both physiological and biophysical perspectives and also providing a basis for further studies on other types of pulmonary surfactants.
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Affiliation(s)
| | - Barbara Bianca Gerbelli
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP 09210-580, Brazil
| | - Franccesca Fornasier
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, RJ 22453-900, Brazil
| | - Adriano B Chaves Filho
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Marcos Yukio Yoshinaga
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Sayuri Miyamoto
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Laura Mortara
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Caroline Dutra Lacerda
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Iolanda Midea Cuccovia
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - André Silva Pimentel
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, RJ 22453-900, Brazil
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Sever N, Miličić G, Bodnar NO, Wu X, Rapoport TA. Mechanism of Lamellar Body Formation by Lung Surfactant Protein B. Mol Cell 2020; 81:49-66.e8. [PMID: 33242393 DOI: 10.1016/j.molcel.2020.10.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/14/2020] [Accepted: 10/28/2020] [Indexed: 11/30/2022]
Abstract
Breathing depends on pulmonary surfactant, a mixture of phospholipids and proteins, secreted by alveolar type II cells. Surfactant requires lamellar bodies (LBs), organelles containing densely packed concentric membrane layers, for storage and secretion. LB biogenesis remains mysterious but requires surfactant protein B (SP-B), which is synthesized as a precursor (pre-proSP-B) that is cleaved during trafficking into three related proteins. Here, we elucidate the functions and cooperation of these proteins in LB formation. We show that the N-terminal domain of proSP-B is a phospholipid-binding and -transfer protein whose activities are required for proSP-B export from the endoplasmic reticulum (ER) and sorting to LBs, the conversion of proSP-B into lipoprotein particles, and neonatal viability in mice. The C-terminal domain facilitates ER export of proSP-B. The mature middle domain, generated after proteolytic cleavage of proSP-B, generates the striking membrane layers characteristic of LBs. Together, our results lead to a mechanistic model of LB biogenesis.
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Affiliation(s)
- Navdar Sever
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Goran Miličić
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Nicholas O Bodnar
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Xudong Wu
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Tom A Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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17
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Loney RW, Panzuela S, Chen J, Yang Z, Fritz JR, Dell Z, Corradi V, Kumar K, Tieleman DP, Hall SB, Tristram-Nagle SA. Location of the Hydrophobic Surfactant Proteins, SP-B and SP-C, in Fluid-Phase Bilayers. J Phys Chem B 2020; 124:6763-6774. [PMID: 32600036 DOI: 10.1021/acs.jpcb.0c03665] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hydrophobic surfactant proteins, SP-B and SP-C, promote rapid adsorption by the surfactant lipids to the surface of the liquid that lines the alveolar air sacks of the lungs. To gain insights into the mechanisms of their function, we used X-ray diffuse scattering (XDS) and molecular dynamics (MD) simulations to determine the location of SP-B and SP-C within phospholipid bilayers. Initial samples contained the surfactant lipids from extracted calf surfactant with increasing doses of the proteins. XDS located protein density near the phospholipid headgroup and in the hydrocarbon core, presumed to be SP-B and SP-C, respectively. Measurements on dioleoylphosphatidylcholine (DOPC) with the proteins produced similar results. MD simulations of the proteins with DOPC provided molecular detail and allowed direct comparison of the experimental and simulated results. Simulations used conformations of SP-B based on other members of the saposin-like family, which form either open or closed V-shaped structures. For SP-C, the amino acid sequence suggests a partial α-helix. Simulations fit best with measurements of XDS for closed SP-B, which occurred at the membrane surface, and SP-C oriented along the hydrophobic interior. Our results provide the most definitive evidence yet concerning the location and orientation of the hydrophobic surfactant proteins.
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Affiliation(s)
- Ryan W Loney
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Sergio Panzuela
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada.,Department of Theoretical Physics and Condensed Matter, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Jespar Chen
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Zimo Yang
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jonathan R Fritz
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Zachary Dell
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Kamlesh Kumar
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Stephen B Hall
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Stephanie A Tristram-Nagle
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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18
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Martinez-Calle M, Prieto M, Olmeda B, Fedorov A, Loura LM, Pérez-Gil J. Pulmonary surfactant protein SP-B nanorings induce the multilamellar organization of surfactant complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183216. [DOI: 10.1016/j.bbamem.2020.183216] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/17/2020] [Accepted: 02/02/2020] [Indexed: 11/25/2022]
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Lipid-Protein and Protein-Protein Interactions in the Pulmonary Surfactant System and Their Role in Lung Homeostasis. Int J Mol Sci 2020; 21:ijms21103708. [PMID: 32466119 PMCID: PMC7279303 DOI: 10.3390/ijms21103708] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022] Open
Abstract
Pulmonary surfactant is a lipid/protein complex synthesized by the alveolar epithelium and secreted into the airspaces, where it coats and protects the large respiratory air–liquid interface. Surfactant, assembled as a complex network of membranous structures, integrates elements in charge of reducing surface tension to a minimum along the breathing cycle, thus maintaining a large surface open to gas exchange and also protecting the lung and the body from the entrance of a myriad of potentially pathogenic entities. Different molecules in the surfactant establish a multivalent crosstalk with the epithelium, the immune system and the lung microbiota, constituting a crucial platform to sustain homeostasis, under health and disease. This review summarizes some of the most important molecules and interactions within lung surfactant and how multiple lipid–protein and protein–protein interactions contribute to the proper maintenance of an operative respiratory surface.
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Liekkinen J, Enkavi G, Javanainen M, Olmeda B, Pérez-Gil J, Vattulainen I. Pulmonary Surfactant Lipid Reorganization Induced by the Adsorption of the Oligomeric Surfactant Protein B Complex. J Mol Biol 2020; 432:3251-3268. [DOI: 10.1016/j.jmb.2020.02.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/22/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022]
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Structure and function of the endothelial surface layer: unraveling the nanoarchitecture of biological surfaces. Q Rev Biophys 2019; 52:e13. [PMID: 31771669 DOI: 10.1017/s0033583519000118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Among the unsolved mysteries of modern biology is the nature of a lining of blood vessels called the 'endothelial surface layer' or ESL. In venous micro-vessels, it is half a micron in thickness. The ESL is 10 times thicker than the endothelial glycocalyx (eGC) at its base, has been presumed to be comprised mainly of water, yet is rigid enough to exclude red blood cells. How is this possible? Developments in physical chemistry suggest that the venous ESL is actually comprised of nanobubbles of CO2, generated from tissue metabolism, in a foam nucleated in the eGC. For arteries, the ESL is dominated by nanobubbles of O2 and N2 from inspired air. The bubbles of the foam are separated and stabilized by thin layers of serum electrolyte and proteins, and a palisade of charged polymer strands of the eGC. The ESL seems to be a respiratory organ contiguous with the flowing blood, an extension of, and a 'lung' in miniature. This interpretation may have far-reaching consequences for physiology.
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Permeation of beta-defensin-3 encapsulated with polyethylene glycol in lung surfactant models at air-water interface. Colloids Surf B Biointerfaces 2019; 182:110357. [DOI: 10.1016/j.colsurfb.2019.110357] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 07/07/2019] [Accepted: 07/08/2019] [Indexed: 11/21/2022]
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23
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Martínez-Calle M, Alonso A, Pérez-Gil J, Olmeda B. Native supramolecular protein complexes in pulmonary surfactant: Evidences for SP-A/SP-B interactions. J Proteomics 2019; 207:103466. [DOI: 10.1016/j.jprot.2019.103466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/08/2019] [Accepted: 07/22/2019] [Indexed: 12/21/2022]
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Nanocarrier Lipid Composition Modulates the Impact of Pulmonary Surfactant Protein B (SP-B) on Cellular Delivery of siRNA. Pharmaceutics 2019; 11:pharmaceutics11090431. [PMID: 31450805 PMCID: PMC6781292 DOI: 10.3390/pharmaceutics11090431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 12/17/2022] Open
Abstract
Two decades since the discovery of the RNA interference (RNAi) pathway, we are now witnessing the approval of the first RNAi-based treatments with small interfering RNA (siRNA) drugs. Nevertheless, the widespread use of siRNA is limited by various extra- and intracellular barriers, requiring its encapsulation in a suitable (nanosized) delivery system. On the intracellular level, the endosomal membrane is a major barrier following endocytosis of siRNA-loaded nanoparticles in target cells and innovative materials to promote cytosolic siRNA delivery are highly sought after. We previously identified the endogenous lung surfactant protein B (SP-B) as siRNA delivery enhancer when reconstituted in (proteo) lipid-coated nanogels. It is known that the surface-active function of SP-B in the lung is influenced by the lipid composition of the lung surfactant. Here, we investigated the role of the lipid component on the siRNA delivery-promoting activity of SP-B proteolipid-coated nanogels in more detail. Our results clearly indicate that SP-B prefers fluid membranes with cholesterol not exceeding physiological levels. In addition, SP-B retains its activity in the presence of different classes of anionic lipids. In contrast, comparable fractions of SP-B did not promote the siRNA delivery potential of DOTAP:DOPE cationic liposomes. Finally, we demonstrate that the beneficial effect of lung surfactant on siRNA delivery is not limited to lung-related cell types, providing broader therapeutic opportunities in other tissues as well.
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Robichaud NAS, Khatami MH, Saika-Voivod I, Booth V. All-Atom Molecular Dynamics Simulations of Dimeric Lung Surfactant Protein B in Lipid Multilayers. Int J Mol Sci 2019; 20:ijms20163863. [PMID: 31398818 PMCID: PMC6719169 DOI: 10.3390/ijms20163863] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/29/2019] [Accepted: 08/06/2019] [Indexed: 02/07/2023] Open
Abstract
Although lung surfactant protein B (SP-B) is an essential protein that plays a crucial role in breathing, the details of its structure and mechanism are not well understood. SP-B forms covalent homodimers, and in this work we use all-atom molecular dynamics simulations to study dimeric SP-B’s structure and its behavior in promoting lipid structural transitions. Four initial system configurations were constructed based on current knowledge of SP-B’s structure and mechanism, and the protein maintained a helicity consistent with experiment in all systems. Several SP-B-induced lipid reorganization behaviors were observed, and regions of the protein particularly important for these activities included SP-B’s “central loop” and “hinge” regions. SP-B dimers with one subunit initially positioned in each of two adjacent bilayers appeared to promote close contact between two bilayers. When both subunits were initially positioned in the same bilayer, SP-B induced the formation of a defect in the bilayer, with water penetrating into the centre of the bilayer. Similarly, dimeric SP-B showed a propensity to interact with preformed interpores in the bilayer. SP-B dimers also promoted bilayer thinning and creasing. This work fleshes out the atomistic details of the dimeric SP-B structures and SP-B/lipid interactions that underlie SP-B’s essential functions.
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Affiliation(s)
- Nicholas A S Robichaud
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada
| | - Mohammad Hassan Khatami
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada
| | - Ivan Saika-Voivod
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada.
| | - Valerie Booth
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada.
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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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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27
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Paget TL, Parkinson-Lawrence EJ, Orgeig S. Interstitial lung disease and surfactant dysfunction as a secondary manifestation of disease: insights from lysosomal storage disorders. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.ddmod.2019.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Guagliardo R, Pérez-Gil J, De Smedt S, Raemdonck K. Pulmonary surfactant and drug delivery: Focusing on the role of surfactant proteins. J Control Release 2018; 291:116-126. [PMID: 30321577 DOI: 10.1016/j.jconrel.2018.10.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/06/2018] [Accepted: 10/08/2018] [Indexed: 11/30/2022]
Abstract
Pulmonary surfactant (PS) has been extensively studied because of its primary role in mammalian breathing. The deposition of this surface-active material at the alveolar air-water interface is essential to lower surface tension, thus avoiding alveolar collapse during expiration. In addition, PS is involved in host defense, facilitating the clearance of potentially harmful particulates. PS has a unique composition, including 92% of lipids and 8% of surfactant proteins (SPs) by mass. Although they constitute the minor fraction, SPs to a large extent orchestrate PS-related functions. PS contains four surfactant proteins (SPs) that can be structurally and functionally divided in two groups, i.e. the large hydrophilic SP-A and SP-D and the smaller hydrophobic SP-B and SP-C. The former belong to the family of collectins and are involved in opsonization processes, thus promoting uptake of pathogens and (nano)particles by phagocytic cell types. The latter SPs regulate interfacial surfactant adsorption dynamics, facilitating (phospho)lipid transfer and membrane fusion processes. In the context of pulmonary drug delivery, the exploitation of PS as a carrier to promote drug spreading along the alveolar interface is gaining interest. In addition, recent studies investigated the interaction of PS with drug-loaded nanoparticles (nanomedicines) following pulmonary administration, which strongly influences their biological fate, drug delivery efficiency and toxicological profile. Interestingly, the specific biophysical mode-of-action of the four SPs affect the drug delivery process of nanomedicines both on the extra-and intracellular level, modulating pulmonary distribution, cell targeting and intracellular delivery. This knowledge can be harnessed to exploit SPs for the design of unique and bio-inspired drug delivery strategies.
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Affiliation(s)
- Roberta Guagliardo
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Department of Pharmaceutics, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Jesús Pérez-Gil
- Departamento de Bioquimica y Biologia Molecular, Facultad de Biologia, Research Institute Hospital 12 Octubre, Universidad Complutense, José Antonio Novais 2, 28040 Madrid, Spain.
| | - Stefaan De Smedt
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Department of Pharmaceutics, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Koen Raemdonck
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Department of Pharmaceutics, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
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Merckx P, De Backer L, Van Hoecke L, Guagliardo R, Echaide M, Baatsen P, Olmeda B, Saelens X, Pérez-Gil J, De Smedt SC, Raemdonck K. Surfactant protein B (SP-B) enhances the cellular siRNA delivery of proteolipid coated nanogels for inhalation therapy. Acta Biomater 2018; 78:236-246. [PMID: 30118853 DOI: 10.1016/j.actbio.2018.08.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/30/2018] [Accepted: 08/13/2018] [Indexed: 12/24/2022]
Abstract
Despite the many advantages of small interfering RNA (siRNA) inhalation therapy and a growing prevalence of respiratory pathologies, its clinical translation is severely hampered by inefficient intracellular delivery. To this end, we previously developed hybrid nanoparticles consisting of an siRNA-loaded nanosized hydrogel core (nanogel) coated with Curosurf®, a clinically used pulmonary surfactant (PS). Interestingly, the PS shell was shown to markedly improve particle stability as well as intracellular siRNA delivery in vitro and in vivo. The major aim of this work was to identify the key molecular components of PS responsible for the enhanced siRNA delivery and evaluate how the complexity of the PS coat could be reduced. We identified surfactant protein B (SP-B) as a potent siRNA delivery enhancer when reconstituted in proteolipid coated hydrogel nanocomposites. Improved cytosolic siRNA delivery was achieved by inserting SP-B into a simplified phospholipid mixture prior to nanogel coating. This effect was observed both in vitro (lung epithelial cell line) and in vivo (murine acute lung injury model), albeit that distinct phospholipids were required to achieve these results. Importantly, the developed nanocomposites have a low in vivo toxicity and are efficiently taken up by resident alveolar macrophages, a main target cell type for treatment of inflammatory pulmonary pathologies. Our results demonstrate the potential of the endogenous protein SP-B as an intracellular siRNA delivery enhancer, paving the way for future design of nanoformulations for siRNA inhalation therapy. STATEMENT OF SIGNIFICANCE Despite the therapeutic potential of small interfering RNA (siRNA) and a growing prevalence of lung diseases for which innovative therapies are needed, a safe and effective siRNA inhalation therapy remains non-existing due to a lack of suitable formulations. We identified surfactant protein B (SP-B) as a potent enhancer of siRNA delivery by proteolipid coated nanogel formulations in vitro in a lung epithelial cell line. The developed nanocomposites have a low in vivo toxicity and show a high uptake by alveolar macrophages, a main target cell type for treatment of inflammatory pulmonary pathologies. Importantly, in vivo SP-B is also critical for the developed formulation to obtain a significant silencing of TNFα in a murine LPS-induced acute lung injury model.
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Ronda L, Pioselli B, Catinella S, Salomone F, Marchetti M, Bettati S. Quenching of tryptophan fluorescence in a highly scattering solution: Insights on protein localization in a lung surfactant formulation. PLoS One 2018; 13:e0201926. [PMID: 30075031 PMCID: PMC6075776 DOI: 10.1371/journal.pone.0201926] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/24/2018] [Indexed: 11/18/2022] Open
Abstract
CHF5633 (Chiesi Farmaceutici, Italy) is a synthetic surfactant developed for respiratory distress syndrome replacement therapy in pre-term newborn infants. CHF5633 contains two phospholipids (dipalmitoylphosphatidylcholine and 1-palmitoyl-2oleoyl-sn-glycero-3-phosphoglycerol sodium salt), and peptide analogues of surfactant protein C (SP-C analogue) and surfactant protein B (SP-B analogue). Both proteins are fundamental for an optimal surfactant activity in vivo and SP-B genetic deficiency causes lethal respiratory failure after birth. Fluorescence emission of the only tryptophan residue present in SP-B analogue (SP-C analogue has none) could in principle be exploited to probe SP-B analogue conformation, localization and interaction with other components of the pharmaceutical formulation. However, the high light scattering activity of the multi-lamellar vesicles suspension characterizing the pharmaceutical surfactant formulation represents a challenge for such studies. We show here that quenching of tryptophan fluorescence and Singular Value Decomposition analysis can be used to accurately calculate and subtract background scattering. The results indicate, with respect to Trp microenvironment, a conformationally homogeneous population of SP-B. Trp is highly accessible to the water phase, suggesting a surficial localization on the membrane of phospholipid vesicles, similarly to what observed for full length SP-B in natural lung surfactant, and supporting an analogous role in protein anchoring to the lipid phase.
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Affiliation(s)
- Luca Ronda
- Department of Medicine and Surgery, University of Parma, Parma, Italy
- Biopharmanet-TEC, University of Parma, Parma, Italy
- * E-mail: (LR); (SB)
| | | | | | | | | | - Stefano Bettati
- Department of Medicine and Surgery, University of Parma, Parma, Italy
- Biopharmanet-TEC, University of Parma, Parma, Italy
- Italian National Institute of Biostructures and Biosystems, Rome, Italy
- * E-mail: (LR); (SB)
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31
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Cabré EJ, Martínez-Calle M, Prieto M, Fedorov A, Olmeda B, Loura LMS, Pérez-Gil J. Homo- and hetero-oligomerization of hydrophobic pulmonary surfactant proteins SP-B and SP-C in surfactant phospholipid membranes. J Biol Chem 2018; 293:9399-9411. [PMID: 29700110 DOI: 10.1074/jbc.ra117.000222] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 03/28/2018] [Indexed: 11/06/2022] Open
Abstract
Pulmonary surfactant is a lipid/protein mixture that reduces surface tension at the respiratory air-water interface in lungs. Among its nonlipidic components are pulmonary surfactant-associated proteins B and C (SP-B and SP-C, respectively). These highly hydrophobic proteins are required for normal pulmonary surfactant function, and whereas past literature works have suggested possible SP-B/SP-C interactions and a reciprocal modulation effect, no direct evidence has been yet identified. In this work, we report an extensive fluorescence spectroscopy study of both intramolecular and intermolecular SP-B and SP-C interactions, using a combination of quenching and FRET steady-state and time-resolved methodologies. These proteins are compartmentalized in full surfactant membranes but not in pure 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) vesicles, in accordance with their previously described preference for liquid disordered phases. From the observed static self-quenching and homo-FRET of BODIPY-FL labeled SP-B, we conclude that this protein forms homoaggregates at low concentration (lipid:protein ratio, 1:1000). Increases in polarization of BODIPY-FL SP-B and steady-state intensity of WT SP-B were observed upon incorporation of under-stoichiometric amounts of WT SP-C. Conversely, Marina Blue-labeled SP-C is quenched by over-stoichiometric amounts of WT SP-B, whereas under-stoichiometric concentrations of the latter actually increase SP-C emission. Time-resolved hetero-FRET from Marina Blue SP-C to BODIPY-FL SP-B confirm distinct protein aggregation behaviors with varying SP-B concentration. Based on these multiple observations, we propose a model for SP-B/SP-C interactions, where SP-C might induce conformational changes on SP-B complexes, affecting its aggregation state. The conclusions inferred from the present work shed light on the synergic functionality of both proteins in the pulmonary surfactant system.
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Affiliation(s)
- Elisa J Cabré
- From the Department of Biochemistry, Faculty of Biology, Complutense University, Madrid 28040, Spain
| | - Marta Martínez-Calle
- From the Department of Biochemistry, Faculty of Biology, Complutense University, Madrid 28040, Spain.,the Hospital 12 Octubre Research Institute, Madrid 28041, Spain
| | - Manuel Prieto
- the CQFM-IN and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa 1049-001, Portugal
| | - Alexander Fedorov
- the CQFM-IN and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa 1049-001, Portugal
| | - Bárbara Olmeda
- From the Department of Biochemistry, Faculty of Biology, Complutense University, Madrid 28040, Spain.,the Hospital 12 Octubre Research Institute, Madrid 28041, Spain
| | - Luís M S Loura
- the Faculty of Pharmacy, University of Coimbra, Coimbra 3000-548, Portugal, and .,the Centro de Química de Coimbra, University of Coimbra, Coimbra 3004-535, Portugal
| | - Jesús Pérez-Gil
- From the Department of Biochemistry, Faculty of Biology, Complutense University, Madrid 28040, Spain, .,the Hospital 12 Octubre Research Institute, Madrid 28041, Spain
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Martínez‐Calle M, Olmeda B, Dietl P, Frick M, Pérez‐Gil J. Pulmonary surfactant protein SP‐B promotes exocytosis of lamellar bodies in alveolar type II cells. FASEB J 2018. [DOI: 10.1096/fj.201701462rr] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Marta Martínez‐Calle
- Department of Biochemistry and Molecular BiologyFaculty of BiologyComplutense UniversityMadridSpain
- Research Institute “Hospital 12 de Octubre”Complutense UniversityMadridSpain
| | - Bárbara Olmeda
- Department of Biochemistry and Molecular BiologyFaculty of BiologyComplutense UniversityMadridSpain
- Research Institute “Hospital 12 de Octubre”Complutense UniversityMadridSpain
| | - Paul Dietl
- Institute of General PhysiologyUlm UniversityUlmGermany
| | - Manfred Frick
- Institute of General PhysiologyUlm UniversityUlmGermany
| | - Jesús Pérez‐Gil
- Department of Biochemistry and Molecular BiologyFaculty of BiologyComplutense UniversityMadridSpain
- Research Institute “Hospital 12 de Octubre”Complutense UniversityMadridSpain
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Ninham BW, Larsson K, Lo Nostro P. Two sides of the coin. Part 2. Colloid and surface science meets real biointerfaces. Colloids Surf B Biointerfaces 2017; 159:394-404. [PMID: 28822288 DOI: 10.1016/j.colsurfb.2017.07.090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/07/2017] [Accepted: 07/31/2017] [Indexed: 12/23/2022]
Abstract
Part 1 revisited developments in lipid and surfactant self assembly over the past 40 years [1]. New concepts emerged. Here we explore how these developments can be used to make sense of and bring order to a range of complex biological phenomena. Together with Part 1, this contribution is a fundamental revision of intuition at the boundaries of Colloid Science and Biological interfaces from a perspective of nearly 50 years. We offer new insights on a unified treatment of self assembly of lipids, surfactants and proteins in the light of developments presented in Part 1. These were in the enabling disciplines in molecular forces, hydration, oil and electrolyte specificity; and in the role of non Euclidean geometries-across the whole gammut of physical, colloid and surface chemistry, biophysics and membrane biology and medicine. It is where the early founders of the cell theory of biology and the physiologists expected advances to occur as D'Arcy Thompson predicted us 100 years ago.
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Affiliation(s)
- Barry W Ninham
- Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia; Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Firenze, Italy
| | - Kåre Larsson
- Camurus Lipid Research Foundation, Ideon Science Park, 22370 Lund, Sweden
| | - Pierandrea Lo Nostro
- Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Firenze, Italy; Fondazione Prof. Enzo Ferroni-Onlus, 50019 Sesto Fiorentino, Firenze, Italy.
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Jin F, Li C. Seawater-drowning-induced acute lung injury: From molecular mechanisms to potential treatments. Exp Ther Med 2017; 13:2591-2598. [PMID: 28587319 PMCID: PMC5450642 DOI: 10.3892/etm.2017.4302] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/26/2017] [Indexed: 01/11/2023] Open
Abstract
Drowning is a crucial public safety problem and is the third leading cause of accidental fatality, claiming ~372,000 lives annually, worldwide. In near-drowning patients, acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is one of the most common complications. Approximately 1/3 of near-drowning patients fulfill the criteria for ALI or ARDS. In the present article, the current literature of near-drowning, pathophysiologic changes and the molecular mechanisms of seawater-drowning-induced ALI and ARDS was reviewed. Seawater is three times more hyperosmolar than plasma, and following inhalation of seawater the hyperosmotic seawater may cause serious injury in the lung and alveoli. The perturbing effects of seawater may be primarily categorized into insufficiency of pulmonary surfactant, blood-air barrier disruption, formation of pulmonary edema, inflammation, oxidative stress, autophagy, apoptosis and various other hypertonic stimulation. Potential treatments for seawater-induced ALI/ARDS were also presented, in addition to suggestions for further studies. A total of nine therapeutic strategies had been tested and all had focused on modulating the over-activated immunoreactions. In conclusion, seawater drowning is a complex injury process and the exact mechanisms and potential treatments require further exploration.
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Affiliation(s)
- Faguang Jin
- Department of Respiratory and Critical Care Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China
| | - Congcong Li
- Department of Respiratory and Critical Care Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China
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Echaide M, Autilio C, Arroyo R, Perez-Gil J. Restoring pulmonary surfactant membranes and films at the respiratory surface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1725-1739. [PMID: 28341439 DOI: 10.1016/j.bbamem.2017.03.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/14/2017] [Accepted: 03/19/2017] [Indexed: 02/08/2023]
Abstract
Pulmonary surfactant is a complex of lipids and proteins assembled and secreted by the alveolar epithelium into the thin layer of fluid coating the respiratory surface of lungs. There, surfactant forms interfacial films at the air-water interface, reducing dramatically surface tension and thus stabilizing the air-exposed interface to prevent alveolar collapse along respiratory mechanics. The absence or deficiency of surfactant produces severe lung pathologies. This review describes some of the most important surfactant-related pathologies, which are a cause of high morbidity and mortality in neonates and adults. The review also updates current therapeutic approaches pursuing restoration of surfactant operative films in diseased lungs, mainly through supplementation with exogenous clinical surfactant preparations. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Mercedes Echaide
- Dept. Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, Madrid, Spain
| | - Chiara Autilio
- Dept. Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, Madrid, Spain
| | - Raquel Arroyo
- Dept. Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, Madrid, Spain
| | - Jesus Perez-Gil
- Dept. Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, Madrid, Spain.
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36
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Sunde M, Pham CLL, Kwan AH. Molecular Characteristics and Biological Functions of Surface-Active and Surfactant Proteins. Annu Rev Biochem 2017; 86:585-608. [PMID: 28125290 DOI: 10.1146/annurev-biochem-061516-044847] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many critical biological processes take place at hydrophobic:hydrophilic interfaces, and a wide range of organisms produce surface-active proteins and peptides that reduce surface and interfacial tension and mediate growth and development at these boundaries. Microorganisms produce both small lipid-associated peptides and amphipathic proteins that allow growth across water:air boundaries, attachment to surfaces, predation, and improved bioavailability of hydrophobic substrates. Higher-order organisms produce surface-active proteins with a wide variety of functions, including the provision of protective foam environments for vulnerable reproductive stages, evaporative cooling, and gas exchange across airway membranes. In general, the biological functions supported by these diverse polypeptides require them to have an amphipathic nature, and this is achieved by a diverse range of molecular structures, with some proteins undergoing significant conformational change or intermolecular association to generate the structures that are surface active.
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Affiliation(s)
- Margaret Sunde
- Discipline of Pharmacology, School of Medical Sciences and Australian Institute for Nanoscale Science and Technology, University of Sydney, NSW 2006, Australia; ,
| | - Chi L L Pham
- Discipline of Pharmacology, School of Medical Sciences and Australian Institute for Nanoscale Science and Technology, University of Sydney, NSW 2006, Australia; ,
| | - Ann H Kwan
- School of Life and Environmental Sciences and Australian Institute for Nanoscale Science and Technology, University of Sydney, NSW 2006, Australia;
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All-atom molecular dynamics simulations of lung surfactant protein B: Structural features of SP-B promote lipid reorganization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3082-3092. [DOI: 10.1016/j.bbamem.2016.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/30/2016] [Accepted: 09/20/2016] [Indexed: 01/07/2023]
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Walther FJ, Gordon LM, Waring AJ. Design of Surfactant Protein B Peptide Mimics Based on the Saposin Fold for Synthetic Lung Surfactants. Biomed Hub 2016; 1. [PMID: 28503550 PMCID: PMC5424708 DOI: 10.1159/000451076] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Surfactant protein (SP)-B is a 79-residue polypeptide crucial for the biophysical and physiological function of endogenous lung surfactant. SP-B is a member of the saposin or saposin-like proteins (SAPLIP) family of proteins that share an overall three-dimensional folding pattern based on secondary structures and disulfide connectivity and exhibit a wide diversity of biological functions. Here, we review the synthesis, molecular biophysics and activity of synthetic analogs of saposin proteins designed to mimic those interactions of the parent proteins with lipids that enhance interfacial activity. Saposin proteins generally interact with target lipids as either monomers or multimers via well-defined amphipathic helices, flexible hinge domains, and insertion sequences. Based on the known 3D-structural motif for the saposin family, we show how bioengineering techniques may be used to develop minimal peptide constructs that maintain desirable structural properties and activities in biomedical applications. One important application is the molecular design, synthesis and activity of Saposin mimics based on the SP-B structure. Synthetic lung surfactants containing active SP-B analogs may be potentially useful in treating diseases of surfactant deficiency or dysfunction including the neonatal respiratory distress syndrome and acute lung injury/acute respiratory distress syndrome.
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Affiliation(s)
- Frans J Walther
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.,Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Larry M Gordon
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Alan J Waring
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.,Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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39
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Notter RH, Gupta R, Schwan AL, Wang Z, Shkoor MG, Walther FJ. Synthetic lung surfactants containing SP-B and SP-C peptides plus novel phospholipase-resistant lipids or glycerophospholipids. PeerJ 2016; 4:e2635. [PMID: 27812430 PMCID: PMC5088750 DOI: 10.7717/peerj.2635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 09/30/2016] [Indexed: 01/22/2023] Open
Abstract
Background This study examines the biophysical and preclinical pulmonary activity of synthetic lung surfactants containing novel phospholipase-resistant phosphonolipids or synthetic glycerophospholipids combined with Super Mini-B (S-MB) DATK and/or SP-Css ion-lock 1 peptides that replicate the functional biophysics of surfactant proteins (SP)-B and SP-C. Phospholipase-resistant phosphonolipids used in synthetic surfactants are DEPN-8 and PG-1, molecular analogs of dipalmitoyl phosphatidylcholine (DPPC) and palmitoyl-oleoyl phosphatidylglycerol (POPG), while glycerophospholipids used are active lipid components of native surfactant (DPPC:POPC:POPG 5:3:2 by weight). The objective of the work is to test whether these novel lipid/peptide synthetic surfactants have favorable preclinical activity (biophysical, pulmonary) for therapeutic use in reversing surfactant deficiency or dysfunction in lung disease or injury. Methods Surface activity of synthetic lipid/peptide surfactants was assessed in vitro at 37 °C by measuring adsorption in a stirred subphase apparatus and dynamic surface tension lowering in pulsating and captive bubble surfactometers. Shear viscosity was measured as a function of shear rate on a Wells-Brookfield micro-viscometer. In vivo pulmonary activity was determined by measuring lung function (arterial oxygenation, dynamic lung compliance) in ventilated rats and rabbits with surfactant deficiency/dysfunction induced by saline lavage to lower arterial PO2 to <100 mmHg, consistent with clinical acute respiratory distress syndrome (ARDS). Results Synthetic surfactants containing 5:3:2 DPPC:POPC:POPG or 9:1 DEPN-8:PG-1 combined with 3% (by wt) of S-MB DATK, 3% SP-Css ion-lock 1, or 1.5% each of both peptides all adsorbed rapidly to low equilibrium surface tensions and also reduced surface tension to ≤1 mN/m under dynamic compression at 37 °C. However, dual-peptide surfactants containing 1.5% S-MB DATK + 1.5% SP-Css ion-lock 1 combined with 9:1 DEPN-8:PG-1 or 5:3:2 DPPC:POPC:POPG had the greatest in vivo activity in improving arterial oxygenation and dynamic lung compliance in ventilated animals with ARDS. Saline dispersions of these dual-peptide synthetic surfactants were also found to have shear viscosities comparable to or below those of current animal-derived surfactant drugs, supporting their potential ease of deliverability by instillation in future clinical applications. Discussion Our findings support the potential of dual-peptide synthetic lipid/peptide surfactants containing S-MB DATK + SP-Css ion-lock 1 for treating diseases of surfactant deficiency or dysfunction. Moreover, phospholipase-resistant dual-peptide surfactants containing DEPN-8/PG-1 may have particular applications in treating direct forms of ARDS where endogenous phospholipases are present in the lungs.
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Affiliation(s)
- Robert H Notter
- Department of Pediatrics, University of Rochester , Rochester , NY , United States
| | - Rohun Gupta
- Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance , CA , United States
| | - Adrian L Schwan
- Department of Chemistry, University of Guelph , Guelph , Ontario , Canada
| | - Zhengdong Wang
- Department of Pediatrics, University of Rochester , Rochester , NY , United States
| | - Mohanad Gh Shkoor
- Department of Chemistry, University of Guelph , Guelph , Ontario , Canada
| | - Frans J Walther
- Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, United States; Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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Olmeda B, Martínez-Calle M, Pérez-Gil J. Pulmonary surfactant metabolism in the alveolar airspace: Biogenesis, extracellular conversions, recycling. Ann Anat 2016; 209:78-92. [PMID: 27773772 DOI: 10.1016/j.aanat.2016.09.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/22/2016] [Accepted: 09/25/2016] [Indexed: 01/03/2023]
Abstract
Pulmonary surfactant is a lipid-protein complex that lines and stabilizes the respiratory interface in the alveoli, allowing for gas exchange during the breathing cycle. At the same time, surfactant constitutes the first line of lung defense against pathogens. This review presents an updated view on the processes involved in biogenesis and intracellular processing of newly synthesized and recycled surfactant components, as well as on the extracellular surfactant transformations before and after the formation of the surface active film at the air-water interface. Special attention is paid to the crucial regulation of surfactant homeostasis, because its disruption is associated with several lung pathologies.
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Affiliation(s)
- Bárbara Olmeda
- Department of Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, 28040 Madrid, Spain
| | - Marta Martínez-Calle
- Department of Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, 28040 Madrid, Spain
| | - Jesus Pérez-Gil
- Department of Biochemistry, Faculty of Biology, and Research Institute "Hospital 12 de Octubre", Complutense University, 28040 Madrid, Spain.
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Parra E, Kinoshita K, Needham D. Micropipette Technique Study of Natural and Synthetic Lung Surfactants at the Air-Water Interface: Presence of a SP-B Analog Peptide Promotes Membrane Aggregation, Formation of Tightly Stacked Lamellae, and Growth of Myelin Figures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:10570-10581. [PMID: 27653452 DOI: 10.1021/acs.langmuir.6b01420] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present study is a microscopic interfacial characterization of a series of lung surfactant materials performed with the micropipette technique. The advantages of this technique include the measurement of equilibrium and dynamic surface tensions while acquiring structural and dynamic information at microscopic air-water interfaces in real time and upon compression. Here, we characterized a series of animal-derived and synthetic lung surfactant formulations, including native surfactant obtained from porcine lungs (NS); the commercial Curosurf, Infasurf, and Survanta; and a synthetic Super Mini-B (SMB)-containing formulation. It was observed that the presence of the natural hydrophobic proteins and, more strikingly, the peptide SMB, promoted vesicle condensation as thick membrane stacks beneath the interface. Only in the presence of SMB, these stacks underwent spontaneous structural transformations, consisting of the nucleation and growth of microtubes and in some cases their subsequent coiling into helices. The dimensions of these tubes (2-15 μm diameter) and their linear (2-3 μm/s) and volumetric growth rates (20-30 μm3/s) were quantified, and no specific effects were found on them for increasing SMB concentrations from 0.1 to 4%. Nevertheless, a direct correlation between the number of tubes and SMB contents was found, suggesting that SMB molecules are the promoters of tube nucleation in these membranes. A detailed analysis of the tube formation process was performed following previous models for the growth of myelin figures, proposing a combined mechanism between dehydration-rehydration of the lipid bilayers and induction of mechanical defects by SMB that would act as nucleation sites for the tubes. The formation of tubes was also observed in Infasurf, and in NS only after subsequent expansion and compression but neither in the other clinical surfactants nor in protein-free preparations. Finally, the connection between this data and the observations from the lung surfactant literature concerning the widely reported "near-zero surface tension" for lung surfactant films and intact alveolar surfaces is also discussed.
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Affiliation(s)
- Elisa Parra
- Center for Single Particle Science and Engineering (SPSE), Southern Denmark University , Campusvej 55, DK-5230 Odense, Denmark
| | - Koji Kinoshita
- Center for Single Particle Science and Engineering (SPSE), Southern Denmark University , Campusvej 55, DK-5230 Odense, Denmark
| | - David Needham
- Center for Single Particle Science and Engineering (SPSE), Southern Denmark University , Campusvej 55, DK-5230 Odense, Denmark
- Department of Mechanical Engineering and Material Science, Duke University , Durham, North Carolina 90300, United States
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Hobi N, Giolai M, Olmeda B, Miklavc P, Felder E, Walther P, Dietl P, Frick M, Pérez-Gil J, Haller T. A small key unlocks a heavy door: The essential function of the small hydrophobic proteins SP-B and SP-C to trigger adsorption of pulmonary surfactant lamellar bodies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2124-34. [DOI: 10.1016/j.bbamcr.2016.04.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/15/2016] [Accepted: 04/27/2016] [Indexed: 02/07/2023]
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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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