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Roeder F, Knudsen L, Schmiedl A. The expression of the surfactant proteins SP-A and SP-B during postnatal alveolarization of the rat lung. PLoS One 2024; 19:e0297889. [PMID: 38483982 PMCID: PMC10939297 DOI: 10.1371/journal.pone.0297889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/03/2024] [Indexed: 03/17/2024] Open
Abstract
OBJECTIVE Surfactant-specific proteins (SP) are responsible for the functional and structural integrity as well as for the stabilization of the intra-alveolar surfactant. Morphological lung maturation starts in rat lungs after birth. The aim of this study was to investigate whether the expression of the hydrophilic SP-A and the hydrophobic SP-B is associated with characteristic postnatal changes characterizing morphological lung maturation. METHODS Stereological methods were performed on the light microscope. Using immunohistochemical and molecular biological methods (Western Blot, RT-qPCR), the SP-A and SP-B of adult rat lungs and of those with different postnatal developmental stages (3, 7, 14 and 21 days after birth) were characterized. RESULTS As signs of alveolarization the total septal surface and volume increased and the septal thickness decreased. The significantly highest relative surface fraction of SP-A labeled alveolar epithelial cells type II (AEII) was found together with the highest relative SP-A gene expression before the alveolarization (3th postnatal day). With the downregulation of SP-A gene expression during and after alveolarization (between postnatal days 7 and 14), the surface fraction of the SP-A labeled AEII also decreased, so they are lowest in adult animals. The surface fraction of SP-B labeled AEII and the SP-B gene expression showed the significantly highest levels in adults, the protein expression increased also significantly at the end of morphological lung maturation. There were no alterations in the SP-B expression before and during alveolarization until postnatal day 14. The protein expression as well as the gene expression of SP-A and SP-B correlated very well with the total surface of alveolar septa independent of the postnatal age. CONCLUSION The expression of SP-A and SP-B is differentially associated with morphological lung maturation and correlates with increased septation of alveoli as indirect clue for alveolarization.
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Affiliation(s)
- Franziska Roeder
- Institute of Functional and Applied Anatomy, Medical Hannover School, Hannover, Germany
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Medical Hannover School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
| | - Andreas Schmiedl
- Institute of Functional and Applied Anatomy, Medical Hannover School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
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2
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The lung surfactant activity probed with molecular dynamics simulations. Adv Colloid Interface Sci 2022; 304:102659. [PMID: 35421637 DOI: 10.1016/j.cis.2022.102659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 01/17/2023]
Abstract
The surface of pulmonary alveolar subphase is covered with a mixture of lipids and proteins. This lung surfactant plays a crucial role in lung functioning. It shows a complex phase behavior which can be altered by the interaction with third molecules such as drugs or pollutants. For studying multicomponent biological systems, it is of interest to couple experimental approach with computational modelling yielding atomic-scale information. Simple two, three, or four-component model systems showed to be useful for getting more insight in the interaction between lipids, lipids and proteins or lipids and proteins with drugs and impurities. These systems were studied theoretically using molecular dynamic simulations and experimentally by means of the Langmuir technique. A better understanding of the structure and behavior of lung surfactants obtained from this research is relevant for developing new synthetic surfactants for efficient therapies, and may contribute to public health protection.
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3
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Impact of Ozone, Sex, and Gonadal Hormones on Bronchoalveolar Lavage Characteristics and Survival in SP-A KO Mice Infected with Klebsiella pneumoniae. Microorganisms 2020; 8:microorganisms8091354. [PMID: 32899781 PMCID: PMC7563396 DOI: 10.3390/microorganisms8091354] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/30/2020] [Accepted: 09/02/2020] [Indexed: 02/03/2023] Open
Abstract
Surfactant protein A (SP-A) plays an important role in innate immunity. The sex-dependent survival of infected SP-A knockout (KO) mice has been observed. Our goal was to study the impact of ozone (O3) and sex, as well as gonadal hormones, on the bronchoalveolar lavage (BAL) readouts and survival, respectively, of Klebsiella pneumoniae-infected SP-A KO mice. Male and female SP-A KO mice were exposed to O3 or filtered air and infected with K. pneumoniae. We studied markers of inflammation and tissue damage at 4, 24, and 48 h, as well as the survival over 14 days, of gonadectomized (Gx) mice implanted with control pellets (CoP) or hormone (5α-dihydrotestosterone (DHT) in female gonadectomized mice (GxF) or 17β-estradiol (E2) in male gonadectomized mice (GxM)). We observed: (1) an increase in neutrophil and macrophage inflammatory protein-2 levels as time progressed post-infection, and O3 exposure appeared to increase this response; (2) an increase in lactate dehydrogenase, total protein, oxidized protein, and phospholipids in response to O3 with no consistent sex differences in studied parameters; and (3) a reduction in survival of the GxM and CoP mice, the GxM and E2 mice, and the GxF and DHT mice but not for the GxF and CoP mice after O3. Without SP-A, (a) sex was found to have a minimal impact on BAL cellular composition and tissue damage markers, and (b) the impact of gonadal hormones on survival was found to involve different mechanisms than in the presence of SP-A.
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Zhang X, Chu X, Weng B, Gong X, Cai C. An Innovative Model of Bronchopulmonary Dysplasia in Premature Infants. Front Pediatr 2020; 8:271. [PMID: 32537448 PMCID: PMC7267036 DOI: 10.3389/fped.2020.00271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/29/2020] [Indexed: 02/02/2023] Open
Abstract
Bronchopulmonary dysplasia (BPD) is one of the common chronic lung diseases (CLD) of premature infants, which causes unpredictable consequences to the family and society. Therefore, the pathogenesis and prevention methods of BPD are the focus of current research, and the establishment of an effective and appropriate animal model of BPD in premature infants is the key to the research. In this study, premature rats were exposed to hyperoxia environment. Compared with the air group, the body weight and alveolar radiation count of the hyperoxia group decreased significantly, but there was no significant difference in body length. HE staining was used to observe the pathological changes of BPD in the lung tissue. The above results proved that under the hyperoxia condition, the BPD animal model of premature infants was successfully established, which provided a new choice for the future research of BPD.
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Affiliation(s)
- Xiaoyue Zhang
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoyun Chu
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Bowen Weng
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaohui Gong
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Cheng Cai
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
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5
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Schmiedl A, Roolfs T, Tutdibi E, Gortner L, Monz D. Influence of prenatal hypoxia and postnatal hyperoxia on morphologic lung maturation in mice. PLoS One 2017; 12:e0175804. [PMID: 28426693 PMCID: PMC5398543 DOI: 10.1371/journal.pone.0175804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 03/31/2017] [Indexed: 01/15/2023] Open
Abstract
Background Oxygen supply as a lifesaving intervention is frequently used to treat preterm infants suffering additionally from possible prenatal or perinatal pathogen features. The impact of oxygen and/or physical lung injury may influence the morphological lung development, leading to a chronic postnatal lung disease called bronchopulmonary dysplasia (BPD). At present different experimental BPD models are used. However, there are no systematic comparative studies regarding different influences of oxygen on morphological lung maturation. Objective We investigated the influence of prenatal hypoxia and/or postnatal hyperoxia on morphological lung maturation based on stereological parameters, to find out which model best reflects morphological changes in lung development comparable with alterations found in BPD. Methods Pregnant mice were exposed to normoxia, the offspring to normoxia (No/No) or to hyperoxia (No/Hyper). Furthermore, pregnant mice were exposed to hypoxia and the offspring to normoxia (Hypo/No) or to hyperoxia (Hypo/Hyper). Stereological investigations were performed on all pups at 14 days after birth. Results Compared to controls (No/No) 1) the lung volume was significantly reduced in the No/Hyper and Hypo/Hyper groups, 2) the volume weighted mean volume of the parenchymal airspaces was significantly higher in the Hypo/Hyper group, 3) the total air space volume was significantly lower in the No/Hyper and Hypo/Hyper groups, 4) the total septal surface showed significantly lower values in the No/Hyper and Hypo/Hyper groups, 5) the wall thickness of septa showed the highest values in the Hypo/Hyper group without reaching significance, 6) the volume density and the volume weighted mean volume of lamellar bodies in alveolar epithelial cells type II (AEII) were significantly lower in the Hypo/Hyper group. Conclusion Prenatal hypoxia and postnatal hyperoxia differentially influence the maturation of lung parenchyma. In 14 day old mice a significant retardation of morphological lung development leading to BPD-like alterations indicated by different parameters was only seen after hypoxia and hyperoxia.
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Affiliation(s)
- Andreas Schmiedl
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage und Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
- REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany
| | - Torge Roolfs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Erol Tutdibi
- Department of Pediatrics and Neonatology, Saarland University, Homburg/Saar, Germany
| | - Ludwig Gortner
- Department of Pediatrics and Neonatology, Saarland University, Homburg/Saar, Germany
| | - Dominik Monz
- Department of Pediatrics and Neonatology, Saarland University, Homburg/Saar, Germany
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6
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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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7
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Willführ A, Brandenberger C, Piatkowski T, Grothausmann R, Nyengaard JR, Ochs M, Mühlfeld C. Estimation of the number of alveolar capillaries by the Euler number (Euler-Poincaré characteristic). Am J Physiol Lung Cell Mol Physiol 2015; 309:L1286-93. [PMID: 26432874 DOI: 10.1152/ajplung.00410.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 09/25/2015] [Indexed: 11/22/2022] Open
Abstract
The lung parenchyma provides a maximal surface area of blood-containing capillaries that are in close contact with a large surface area of the air-containing alveoli. Volume and surface area of capillaries are the classic stereological parameters to characterize the alveolar capillary network (ACN) and have provided essential structure-function information of the lung. When loss (rarefaction) or gain (angiogenesis) of capillaries occurs, these parameters may not be sufficient to provide mechanistic insight. Therefore, it would be desirable to estimate the number of capillaries, as it contains more distinct and mechanistically oriented information. Here, we present a new stereological method to estimate the number of capillary loops in the ACN. One advantage of this method is that it is independent of the shape, size, or distribution of the capillaries. We used consecutive, 1 μm-thick sections from epoxy resin-embedded material as a physical disector. The Euler-Poincaré characteristic of capillary networks can be estimated by counting the easily recognizable topological constellations of "islands," "bridges," and "holes." The total number of capillary loops in the ACN can then be calculated from the Euler-Poincaré characteristic. With the use of the established estimator of alveolar number, it is possible to obtain the mean number of capillary loops per alveolus. In conclusion, estimation of alveolar capillaries by design-based stereology is an efficient and unbiased method to characterize the ACN and may be particularly useful for studies on emphysema, pulmonary hypertension, or lung development.
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Affiliation(s)
- Alper Willführ
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | | | - Tanja Piatkowski
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Roman Grothausmann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Jens Randel Nyengaard
- Stereology and Electron Microscopy Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus, Denmark
| | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research, Hannover, Germany; and Cluster of Excellence REBIRTH, Hannover, Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research, Hannover, Germany; and Cluster of Excellence REBIRTH, Hannover, Germany
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8
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Tahedl D, Wirkes A, Tschanz SA, Ochs M, Mühlfeld C. How common is the lipid body-containing interstitial cell in the mammalian lung? Am J Physiol Lung Cell Mol Physiol 2014; 307:L386-94. [PMID: 24973404 DOI: 10.1152/ajplung.00131.2014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pulmonary lipofibroblasts are thought to be involved in lung development, regeneration, vitamin A storage, and surfactant synthesis. Most of the evidence for these important functions relies on mouse or rat studies. Therefore, the present study was designed to investigate the presence of lipofibroblasts in a variety of early postnatal and adult mammalian species (including humans) to evaluate the ability to generalize functions of this cell type for other species. For this purpose, lung samples from 14 adult mammalian species as well as from postnatal mice, rats, and humans were investigated using light and electron microscopic stereology to obtain the volume fraction and the total volume of lipid bodies. In adult animals, lipid bodies were observed only, but not in all rodents. In all other species, no lipofibroblasts were observed. In rodents, lipid body volume scaled with body mass with an exponent b = 0.73 in the power law equation. Lipid bodies were not observed in postnatal human lungs but showed a characteristic postnatal increase in mice and rats and persisted at a lower level in the adult animals. Among 14 mammalian species, lipofibroblasts were only observed in rodents. The great increase in lipid body volume during early postnatal development of the mouse lung confirms the special role of lipofibroblasts during rodent lung development. It is evident that the cellular functions of pulmonary lipofibroblasts cannot be transferred easily from rodents to other species, in particular humans.
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Affiliation(s)
- Daniel Tahedl
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - André Wirkes
- Institute of Anatomy and Cell Biology, Justus-Liebig-University Gießen, Gießen, Germany
| | | | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany; and Cluster of Excellence REBIRTH (From Regenerative Biology to Reconstructive Therapy), Hannover, Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany; and Cluster of Excellence REBIRTH (From Regenerative Biology to Reconstructive Therapy), Hannover, Germany
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9
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Wirkes A, Jung K, Ochs M, Mühlfeld C. Allometry of the mammalian intracellular pulmonary surfactant system. J Appl Physiol (1985) 2010; 109:1662-9. [DOI: 10.1152/japplphysiol.00674.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alveolar epithelial (AE) surface area is closely correlated with body mass (BM) in mammals. The AE is covered by a surfactant layer produced by alveolar epithelial type II (AE2) cells. We hypothesized that the total number of AE2 cells and the volume of intracellular surfactant-storing lamellar bodies (Lb) are correlated with BM with a similar slope as AE surface area. We used light and electron microscopic stereology to estimate the number and mean volume of AE2 cells and the total volume of Lb in 12 mammalian species ranging from 2 to 3 g (Etruscan shrew) to 400–500 kg (horse) BM. The mean size of Lb was evaluated using the volume-weighted mean volume and the volume-to-surface ratio of Lb. The mean volume of AE2 cells was 500–600 μm3 in most species, but was higher in Etruscan shrew, guinea pig, and human lung. The mean volume of Lb per AE2 cell was 80–100 μm3 in most species, with the same exceptions as above. However, the total number of AE2 cells and the total volume of Lb were closely correlated with BM and exhibited an allometric relationship similar to the slope of AE surface area. The mean size of Lb was similar in all investigated species. In conclusion, the mean volume of AE2 cells and their Lb are independent of BM but show some interspecific variations. The adaptation of the intracellular surfactant pool size to BM is obtained by the variation of the number of AE2 cells in the lung.
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Affiliation(s)
- André Wirkes
- Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Kristina Jung
- Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Matthias Ochs
- Institute of Anatomy, University of Bern, Bern, Switzerland; and
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Christian Mühlfeld
- Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Giessen, Germany
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Pynn CJ, Picardi MV, Nicholson T, Wistuba D, Poets CF, Schleicher E, Perez-Gil J, Bernhard W. Myristate is selectively incorporated into surfactant and decreases dipalmitoylphosphatidylcholine without functional impairment. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1306-16. [DOI: 10.1152/ajpregu.00380.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lung surfactant mainly comprises phosphatidylcholines (PC), together with phosphatidylglycerols and surfactant proteins SP-A to SP-D. Dipalmitoyl-PC (PC16:0/16:0), palmitoylmyristoyl-PC (PC16:0/14:0), and palmitoylpalmitoleoyl-PC (PC16:0/16:1) together comprise 75–80% of surfactant PC. During alveolarization, which occurs postnatally in the rat, PC16:0/14:0 reversibly increases at the expense of PC16:0/16:0. As lipoproteins modify surfactant metabolism, we postulated an extrapulmonary origin of PC16:0/14:0 enrichment in surfactant. We, therefore, fed rats (d19–26) with trilaurin (C12:03), trimyristin (C14:03), tripalmitin (C16:03), triolein (C18:13) or trilinolein (C18:23) vs. carbohydrate diet to assess their effects on surfactant PC composition and surface tension function using a captive bubble surfactometer. Metabolism was assessed with deuterated C12:0 (ω-d3-C12:0) and ω-d3-C14:0. C14:03 increased PC16:0/14:0 in surfactant from 12 ± 1 to 45 ± 3% and decreased PC16:0/16:0 from 47 ± 1 to 29 ± 2%, with no impairment of surface tension function. Combined phospholipase A2 assay and mass spectrometry revealed that 50% of the PC16:0/14:0 peak comprised its isomer 1-myristoyl-2-palmitoyl-PC (PC14:0/16:0). While C12:03 was excluded from incorporation into PC, it increased PC16:0/14:0 as well. C16:03, C18:13, and C18:23 had no significant effect on PC16:0/16:0 or PC16:0/14:0. d3-C14:0 was enriched in lung PC, either via direct supply or via d3-C12:0 elongation. Enrichment of d3-C14:0 in surfactant PC contrasted its rapid turnover in plasma and liver PC, where its elongation product d3-C16:0 surmounted d3-C14:0. In summary, high surfactant PC16:0/14:0 during lung development correlates with C14:0 and C12:0 supply via specific C14:0 enrichment into lung PC. Surfactant that is high in PC16:0/14:0 but low in PC16:0/16:0 is compatible with normal respiration and surfactant function in vitro.
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Affiliation(s)
- Christopher J. Pynn
- Departments of 1Neonatology and
- Internal Medicine IV, Faculty of Medicine, and
| | - M. Victoria Picardi
- Department of Bioquimica y Biologia Molecular, Universidad Complutense, Madrid, Spain
| | - Tim Nicholson
- Department of Chemistry, Eberhard-Karls-University, Tübingen, Germany; and
| | - Dorothee Wistuba
- Department of Chemistry, Eberhard-Karls-University, Tübingen, Germany; and
| | | | | | - Jesus Perez-Gil
- Department of Bioquimica y Biologia Molecular, Universidad Complutense, Madrid, Spain
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11
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Fisher AB, Dodia C, Ruckert P, Tao JQ, Bates SR. Pathway to lamellar bodies for surfactant protein A. Am J Physiol Lung Cell Mol Physiol 2010; 299:L51-8. [PMID: 20382745 DOI: 10.1152/ajplung.00066.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alveolar surfactant protein A (SP-A) is endocytosed by type II epithelial cells through clathrin-dependent uptake and targeted to lamellar bodies for resecretion. However, the mechanism for secretion of newly synthesized SP-A, whether regulated exocytosis of lamellar bodies or constitutive secretion, is unresolved. If it is the latter, lamellar body SP-A would represent endocytosed protein. Amantadine, an inhibitor of clathrin-coated vesicle budding, was used to evaluate the role of endocytosis in accumulation of SP-A in lamellar bodies. In isolated rat lungs, amantadine (10 mM) inhibited uptake of endotracheally instilled (35)S-labeled biosynthesized surfactant proteins by >80%. To study trafficking of newly synthesized SP-A, lungs were perfused for up to 6 h with [(35)S]methionine, and surfactant was isolated from lung lavage fluid and lamellar bodies were isolated from lung homogenate. With control lungs, the mean specific activity of [(35)S]SP-A (disintegrations per minute per microgram of SP-A) increased linearly with time of perfusion: it was significantly higher in isolated lamellar bodies than in surfactant and was increased in both compartments by 50-60% in the presence of 0.1 mM 8-bromo-cAMP. These results suggest a precursor-product relationship between lamellar body and extracellular [(35)S]SP-A. Specific activities in both compartments were unaffected by addition of amantadine (10 mM) to the lung perfusate, indicating that uptake from the alveolar space was not responsible for the increase in lamellar body [(35)S]SP-A. Thus the pathway for secretion of newly synthesized SP-A is by transfer from the site of synthesis to the storage/secretory organelle prior to lamellar body exocytosis.
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Affiliation(s)
- Aron B Fisher
- Institute for Environmental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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12
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Malashenko A, Tsuda A, Haber S. Propagation and breakup of liquid menisci and aerosol generation in small airways. J Aerosol Med Pulm Drug Deliv 2010; 22:341-53. [PMID: 19580367 DOI: 10.1089/jamp.2008.0696] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Droplets exhaled during normal breathing and not associated with coughing may pose hazardous agents to infective diseases dissemination. The objective is to explore the physical mechanism, which may lead to droplets formation. METHODS We hypothesize that liquid menisci occlusions, which may form inside small airways, travel along the airway, may lose mass and finally disintegrate into small droplets. This hypothesis was numerically investigated applying physiologically plausible values of the phenomenological coefficients and geometrical conformations. RESULTS We show that three important dimensionless parameters control the motion and disintegration of menisci: the dimensionless mucus layer thickness, the dimensionless menisci initial thickness (all scaled by the airway radius), and the capillary number. Menisci traveling within airways may either remain at equilibrium or diminish or increase in size. Menisci that diminish in size may collapse into the mucus layer; form a large droplet that contains most of the menisci mass before disintegration; or form a larger number of small droplets (we show the forming of three or four droplets in a single occluded airway). CONCLUSIONS A critical capillary number for menisci at equilibrium could be defined. It was shown that menisci tend to diminish in size as the capillary number increases above the critical value, and a number of small droplets may be formed during normal breathing.
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Wang G, Guo X, Diangelo S, Thomas NJ, Floros J. Humanized SFTPA1 and SFTPA2 transgenic mice reveal functional divergence of SP-A1 and SP-A2: formation of tubular myelin in vivo requires both gene products. J Biol Chem 2010; 285:11998-2010. [PMID: 20048345 DOI: 10.1074/jbc.m109.046243] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein A (SP-A) plays a role in lung innate immunity and surfactant-related functions. Two functional genes, SP-A1 (SFTPA1) and SP-A2 (SFTPA2), are present in humans and primates (rodents have one gene). Single gene SP-A1 or SP-A2 proteins expressed in vitro are functional. To study their role in vivo, we generated humanized transgenic (hTG) C57BL/6 mice, SP-A1(6A(4)) and SP-A2(1A(3)). The SP-A cDNA in experimental constructs was driven by the 3.7-kb SP-C promoter. Positive hTG mice were bred with SP-A knock-out mice to generate F8 offspring for study. Epithelial alveolar type II cells were SP-A-positive, and Clara cells were negative by immunohistochemistry in hTG mice. The levels of SP-A in lungs of two hTG lines used were comparable with those in human lungs. Southern blot analysis indicated that two cDNA copies of either SP-A1(6A(4)) or SP-A2(1A(3)) were integrated as a concatemer into the genome of each of the two hTG lines. Electron microscopy analysis revealed that hTG mice with a single SP-A1(6A(4)) or SP-A2(1A(3)) gene product lacked tubular myelin (TM), but hTG mice carrying both had TM. Furthermore, TM was observed in human bronchoalveolar lavage fluid only if both SP-A1 and SP-A2 gene products were present and not in those containing primarily (>99.7%) either SP-A1 or SP-A2 gene products. In vivo rescue study confirmed that TM can only be restored after administering exogenous SP-A containing both SP-A1 and SP-A2 into the lungs of SP-A knock-out mice. These observations indicate that SP-A1 and SP-A2 diverged functionally at least in terms of TM formation.
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Affiliation(s)
- Guirong Wang
- Penn State Center for Host Defense, Inflammation, and Lung Disease Research, Department of Pediatrics, Penn State HersheyCollege ofMedicine, Pennsylvania State University, Hershey, Pennsylvania 17033, USA
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Schefzyk M, Bruder M, Schmiedl A, Stephan M, Kapp A, Wedi B, Raap U. Eosinophil granulocytes: functional differences of a new isolation kit compared to the isolation with anti-CD16-conjugated MicroBeads. Exp Dermatol 2009; 18:653-5. [DOI: 10.1111/j.1600-0625.2008.00824.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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15
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Wong-Riley MTT, Liu Q. Neurochemical and physiological correlates of a critical period of respiratory development in the rat. Respir Physiol Neurobiol 2009; 164:28-37. [PMID: 18524695 DOI: 10.1016/j.resp.2008.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 04/22/2008] [Accepted: 04/22/2008] [Indexed: 01/27/2023]
Abstract
Despite its vital importance to life, respiration is not mature at birth in mammals, but rather, it undergoes a great deal of growth, refinement, and adjustments postnatally. Many adjustments do not follow smooth paths, but assume abrupt changes during certain postnatal periods that may render the animal less capable of responding to respiratory stressors. The present review focuses on neurochemical and physiological correlates of a critical period of respiratory development in the rat. In addition to an imbalanced expression of reduced excitatory and enhanced inhibitory neurotransmitters, a switch in the expressions of gamma-aminobutyric acid (GABA)A receptor subunits from alpha3 to alpha1 occurs around postnatal day (P)12 in the pre-Bötzinger nucleus and the ventrolateral subnucleus of the solitary tract nucleus. Possible subunit switches in a number of other neurotransmitter receptors are discussed. These neurochemical changes are paralleled by ventilatory adjustments at the end of the second postnatal week. At P13 and under normoxia, respiratory frequency reaches its peak before assuming a gradual fall, and both tidal volume and minute ventilation exhibit a significant rise prior to a plateau or a gradual decline until P21. The response to acute hypoxia is markedly reduced between P12 and P16, being lowest at P13. Thus, the end of the second postnatal week can be considered as a critical period of respiratory development, during which multiple neurochemical and physiological adjustments and switches are orchestrated at the same time, rendering the system extremely dynamic but, at the same time, vulnerable to externally imposed perturbations and insults. The critical period embodies a time of multi-system, multifaceted growth and adjustments. It is a plastic, transitional period that is also a part of the normal development of the respiratory system.
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Affiliation(s)
- Margaret T T Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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MOON C, JEONG J, SHIN MK, MIN DS, SHIN T. Expression of Phospholipase D Isozymes in Mouse Lungs during Postnatal Development. J Vet Med Sci 2009; 71:965-8. [DOI: 10.1292/jvms.71.965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Changjong MOON
- Department of Veterinary Anatomy, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University
| | - Jinwoo JEONG
- Department of Veterinary Anatomy, College of Veterinary Medicine and Applied Radiological Science Research Institute, Jeju National University
| | - Min Kyoung SHIN
- Department of Molecular Biology, College of Natural Science, Pusan National University
| | - Do Sik MIN
- Department of Molecular Biology, College of Natural Science, Pusan National University
| | - Taekyun SHIN
- Department of Veterinary Anatomy, College of Veterinary Medicine and Applied Radiological Science Research Institute, Jeju National University
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Bernhard W, Schmiedl A, Koster G, Orgeig S, Acevedo C, Poets CF, Postle AD. Developmental changes in rat surfactant lipidomics in the context of species variability. Pediatr Pulmonol 2007; 42:794-804. [PMID: 17659602 DOI: 10.1002/ppul.20657] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lung surfactant comprises mainly phosphatidylcholine (PC) species together with phosphatidylglycerols and surfactant proteins (SP) SP-A to -D. Changes in the concentrations of its principal components dipalmitoyl-PC, palmitoylmyristoyl-PC, palmitoylpalmitoleoyl-PC relative to developmental, structural and physiological differences are only partially understood. Particularly, their attribution to differences in air-liquid interface curvature, compared with dynamic parameters, such as respiratory rate, are controversial. We postulated that during alveolarization the changes in these principal PC components of surfactant differ from those in other phospholipid parameters, and that across endothermic vertebrates their concentrations are related to lung physiology rather than structure. We therefore investigated in rats from postnatal day (d)1 to d42 the pattern of surfactant phospholipids relative to alveolarization (d4-d14), and we discuss these changes in terms of molecular adaptation to pulmonary structure or physiology. Contrary to mammals with advanced alveolarization and increased respiratory rate (RR) at term, concentrations of dipalmitoyl-PC (49-52%) and palmitoylmyristoyl-PC (7-9%) in lung lavage fluid were identical at d1 and d42. At d7-d14, when in rats RR is increased, palmitoyl-myristoyl-PC transiently increased by 2.5- to 3.9-fold at the expense of dipalmitoyl-PC (-32% to 34%) and palmitoyl-palmitoleoyl-PC (-16%). Other lipidomic changes followed essentially different patterns of increase or decrease. Palmitoyl-myristoyl-PC was increased in large aggregates suggesting that it is an integral component of active surfactant. In the overall context of vertebrates, irrespective of age and lung structure, fractions of palmitoyl-myristoyl-PC, dipalmitoyl-PC and palmitoyl-palmitoleoyl-PC correlate with differences in RR rather than alveolar curvature. In adult mammals, however, only concentrations of palmitoyl-palmitoleoyl-PC correlate with RR.
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Affiliation(s)
- Wolfgang Bernhard
- Department of Neonatology, Faculty of Medicine, Eberhard-Karls-University, Tübingen, Germany.
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