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El Haddad L, Lai E, Murthy PKL, Biswas DD, Soufny R, Roger AL, Tata PR, ElMallah MK. GAA deficiency disrupts distal airway cells in Pompe disease. Am J Physiol Lung Cell Mol Physiol 2023; 325:L288-L298. [PMID: 37366541 PMCID: PMC10625827 DOI: 10.1152/ajplung.00032.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/16/2023] [Accepted: 06/21/2023] [Indexed: 06/28/2023] Open
Abstract
Pompe disease is an autosomal recessive glycogen storage disease caused by mutations in the gene that encodes acid alpha-glucosidase (GAA)-an enzyme responsible for hydrolyzing lysosomal glycogen. GAA deficiency results in systemic lysosomal glycogen accumulation and cellular disruption. Glycogen accumulation in skeletal muscles, motor neurons, and airway smooth muscle cells is known to contribute to respiratory insufficiency in Pompe disease. However, the impact of GAA deficiency on the distal alveolar type 1 and type 2 cells (AT1 and AT2) has not been evaluated. AT1 cells rely on lysosomes for cellular homeostasis so that they can maintain a thin barrier for gas exchange, whereas AT2 cells depend on lysosome-like structures (lamellar bodies) for surfactant production. Using a mouse model of Pompe disease, the Gaa-/- mouse, we investigated the consequences of GAA deficiency on AT1 and AT2 cells using histology, pulmonary function and mechanics, and transcriptional analysis. Histological analysis revealed increased accumulation of lysosomal-associated membrane protein 1 (LAMP1) in the Gaa-/- mice lungs. Furthermore, ultrastructural examination showed extensive intracytoplasmic vacuoles enlargement and lamellar body engorgement. Respiratory dysfunction was confirmed using whole body plethysmography and forced oscillometry. Finally, transcriptomic analysis demonstrated dysregulation of surfactant proteins in AT2 cells, specifically reduced levels of surfactant protein D in the Gaa-/- mice. We conclude that GAA enzyme deficiency leads to glycogen accumulation in the distal airway cells that disrupts surfactant homeostasis and contributes to respiratory impairments in Pompe disease.NEW & NOTEWORTHY This research highlights the impact of Pompe disease on distal airway cells. Prior to this work, respiratory insufficiency in Pompe disease was classically attributed to pathology in respiratory muscles and motor neurons. Using the Pompe mouse model, we note significant pathology in alveolar type 1 and 2 cells with reductions in surfactant protein D and disrupted surfactant homeostasis. These novel findings highlight the potential contributions of alveolar pathology to respiratory insufficiency in Pompe disease.
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Affiliation(s)
- Léa El Haddad
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina, United States
| | - Elias Lai
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina, United States
| | | | - Debolina D Biswas
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina, United States
| | - Rania Soufny
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina, United States
| | - Angela L Roger
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina, United States
| | | | - Mai K ElMallah
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina, United States
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2
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Ma H, Li H, Liu C, Seeram NP. Evaluation of cannabidiol's inhibitory effect on alpha-glucosidase and its stability in simulated gastric and intestinal fluids. J Cannabis Res 2021; 3:20. [PMID: 34162444 PMCID: PMC8223390 DOI: 10.1186/s42238-021-00077-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 05/20/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Cannabidiol (CBD) has been reported to have anti-diabetic effects in pre-clinical and clinical studies but its inhibitory effects on α-glucosidase, a carbohydrate hydrolyzing enzyme, remain unknown. Herein, we evaluated CBD's inhibitory effects on α-glucosidase using in vitro assays and computational studies. METHODS CBD's inhibitory effect on α-glucosidase activity was evaluated in a yeast enzymatic assay and by molecular docking. The stability of CBD in simulated gastric and intestinal fluids was evaluated by high-performance liquid chromatography analyses. RESULTS CBD, at 10, 19, 38, 76, 152, 304, 608, and 1216 μM, inhibited α-glucosidase activity with inhibition of 17.1, 20.4, 48.1, 56.6, 59.1, 63.7, 74.1, and 95.4%, respectively. Acarbose, the positive control, showed a comparable inhibitory activity (with 85.1% inhibition at 608 μM). CBD's inhibitory effect on α-glucosidase was supported by molecular docking showing binding energy (-6.39 kcal/mol) and interactions between CBD and the α-glucosidase protein. CBD was stable in simulated gastric and intestinal fluids for two hours (maintained ≥ 90.0%). CONCLUSIONS CBD showed moderate inhibitory effect against yeast α-glucosidase activity and was stable in gastric and intestinal fluids. However, further studies on CBD's anti-α-glucosidase effects using cellular and in vivo models are warranted to support its potential application for the management of type II diabetes mellitus.
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Affiliation(s)
- Hang Ma
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI, 02881, USA.
| | - Huifang Li
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI, 02881, USA
| | - Chang Liu
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI, 02881, USA
| | - Navindra P Seeram
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Rd, Kingston, RI, 02881, USA.
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3
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Hill PJ, Scordo JM, Arcos J, Kirkby SE, Wewers MD, Wozniak DJ, Torrelles JB. Modifications of Pseudomonas aeruginosa cell envelope in the cystic fibrosis airway alters interactions with immune cells. Sci Rep 2017; 7:4761. [PMID: 28684799 PMCID: PMC5500645 DOI: 10.1038/s41598-017-05253-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/25/2017] [Indexed: 11/10/2022] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous environmental organism and an opportunistic pathogen that causes chronic lung infections in the airways of cystic fibrosis (CF) patients as well as other immune-compromised individuals. During infection, P. aeruginosa enters the terminal bronchioles and alveoli and comes into contact with alveolar lining fluid (ALF), which contains homeostatic and antimicrobial hydrolytic activities, termed hydrolases. These hydrolases comprise an array of lipases, glycosidases, and proteases and thus, they have the potential to modify lipids, carbohydrates and proteins on the surface of invading microbes. Here we show that hydrolase levels between human ALF from healthy and CF patients differ. CF-ALF influences the P. aeruginosa cell wall by reducing the content of one of its major polysaccharides, Psl. This CF-ALF induced Psl reduction does not alter initial bacterial attachment to surfaces but reduces biofilm formation. Importantly, exposure of P. aeruginosa to CF-ALF drives the activation of neutrophils and triggers their oxidative response; thus, defining human CF-ALF as a new innate defense mechanism to control P. aeruginosa infection, but at the same time potentially adding to the chronic inflammatory state of the lung in CF patients.
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Affiliation(s)
- Preston J Hill
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Julia M Scordo
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Jesús Arcos
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Stephen E Kirkby
- Nationwide Children's Hospital, Section of Pulmonary Medicine, Columbus, OH, 43205, USA.,Department of Internal Medicine, Pulmonary, Critical Care and Sleep Medicine Division, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Mark D Wewers
- Department of Internal Medicine, Pulmonary, Critical Care and Sleep Medicine Division, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA. .,Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, 43210, USA. .,Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA.
| | - Jordi B Torrelles
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA. .,Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, 43210, USA.
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Moliva JI, Rajaram MVS, Sidiki S, Sasindran SJ, Guirado E, Pan XJ, Wang SH, Ross P, Lafuse WP, Schlesinger LS, Turner J, Torrelles JB. Molecular composition of the alveolar lining fluid in the aging lung. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9633. [PMID: 24584696 PMCID: PMC4082594 DOI: 10.1007/s11357-014-9633-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/14/2014] [Indexed: 06/01/2023]
Abstract
As we age, there is an increased risk for the development of pulmonary diseases, including infections, but few studies have considered changes in lung surfactant and components of the innate immune system as contributing factors to the increased susceptibility of the elderly to succumb to infections. We and others have demonstrated that human alveolar lining fluid (ALF) components, such as surfactant protein (SP)-A, SP-D, complement protein C3, and alveolar hydrolases, play a significant innate immune role in controlling microbial infections. However, there is a lack of information regarding the effect of increasing age on the level and function of ALF components in the lung. Here we addressed this gap in knowledge by determining the levels of ALF components in the aging lung that are important in controlling infection. Our findings demonstrate that pro-inflammatory cytokines, surfactant proteins and lipids, and complement components are significantly altered in the aged lung in both mice and humans. Further, we show that the aging lung is a relatively oxidized environment. Our study provides new information on how the pulmonary environment in old age can potentially modify mucosal immune responses, thereby impacting pulmonary infections and other pulmonary diseases in the elderly population.
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Affiliation(s)
- Juan I. Moliva
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
| | - Murugesan V. S. Rajaram
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
- />Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
| | - Sabeen Sidiki
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
| | - Smitha J. Sasindran
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
| | - Evelyn Guirado
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
| | - Xueliang Jeff Pan
- />Center for Biostatistics, The Ohio State University, Columbus, OH USA
| | - Shu-Hua Wang
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
- />Division of Infectious Diseases, Department of Internal Medicine, The Ohio State University, Columbus, OH USA
| | - Patrick Ross
- />Division of Thoracic Surgery, Department of Surgery, The Ohio State University, Columbus, OH USA
| | - William P. Lafuse
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
- />Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
| | - Larry S. Schlesinger
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
- />Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
| | - Joanne Turner
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
- />Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
| | - Jordi B. Torrelles
- />Center for Microbial Interface Biology, The Ohio State University, Columbus, OH USA
- />Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
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Arcos J, Sasindran SJ, Fujiwara N, Turner J, Schlesinger LS, Torrelles JB. Human lung hydrolases delineate Mycobacterium tuberculosis-macrophage interactions and the capacity to control infection. THE JOURNAL OF IMMUNOLOGY 2011; 187:372-81. [PMID: 21602490 DOI: 10.4049/jimmunol.1100823] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pulmonary surfactant contains homeostatic and antimicrobial hydrolases. When Mycobacterium tuberculosis is initially deposited in the terminal bronchioles and alveoli, as well as following release from lysed macrophages, bacilli are in intimate contact with these lung surfactant hydrolases. We identified and measured several hydrolases in human alveolar lining fluid and lung tissue that, at their physiological concentrations, dramatically modified the M. tuberculosis cell envelope. Independent of their action time (15 min to 12 h), the effects of the hydrolases on the M. tuberculosis cell envelope resulted in a significant decrease (60-80%) in M. tuberculosis association with, and intracellular growth of the bacteria within, human macrophages. The cell envelope-modifying effects of the hydrolases also led to altered M. tuberculosis intracellular trafficking and induced a protective proinflammatory response to infection. These findings add a new concept to our understanding of M. tuberculosis-macrophage interactions (i.e., the impact of lung surfactant hydrolases on M. tuberculosis infection).
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Affiliation(s)
- Jesús Arcos
- Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210, USA
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6
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Uematsu R, Furukawa JI, Nakagawa H, Shinohara Y, Deguchi K, Monde K, Nishimura SI. High Throughput Quantitative Glycomics and Glycoform-focused Proteomics of Murine Dermis and Epidermis. Mol Cell Proteomics 2005; 4:1977-89. [PMID: 16170054 DOI: 10.1074/mcp.m500203-mcp200] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite recent advances in our understanding of the significance of the protein glycosylation, the throughput of protein glycosylation analysis is still too low to be applied to the exhaustive glycoproteomic analysis. Aiming to elucidate the N-glycosylation of murine epidermis and dermis glycoproteins, here we used a novel approach for focused proteomics. A gross N-glycan profiling (glycomics) of epidermis and dermis was first elucidated both qualitatively and quantitatively upon N-glycan derivatization with novel, stable isotope-coded derivatization reagents followed by MALDI-TOF(/TOF) analysis. This analysis revealed distinct features of the N-glycosylation profile of epidermis and dermis for the first time. A high abundance of high mannose type oligosaccharides was found to be characteristic of murine epidermis glycoproteins. Based on this observation, we performed high mannose type glycoform-focused proteomics by direct tryptic digestion of protein mixtures and affinity enrichment. We identified 15 glycoproteins with 19 N-glycosylation sites that carry high mannose type glycans by off-line LC-MALDI-TOF/TOF mass spectrometry. Moreover the relative quantity of microheterogeneity of different glycoforms present at each N-glycan binding site was determined. Glycoproteins identified were often contained in lysosomes (e.g. cathepsin L and gamma-glutamyl hydrolase), lamellar granules (e.g. glucosylceramidase and cathepsin D), and desmosomes (e.g. desmocollin 1, desmocollin 3, and desmoglein). Lamellar granules are organelles found in the terminally differentiating cells of keratinizing epithelia, and desmosomes are intercellular junctions in vertebrate epithelial cells, thus indicating that N-glycosylation of tissue-specific glycoproteins may contribute to increase the relative proportion of high mannose glycans. The striking roles of lysosomal enzymes in epidermis during lipid remodeling and desquamation may also reflect the observed high abundance of high mannose glycans.
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Affiliation(s)
- Rie Uematsu
- Division of Biological Sciences, Graduate School of Science, Frontier Research Center for Post-Genomic Science and Technology, Hokkaido University, Sapporo 001-0021, Japan
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Lajoie P, Guay G, Dennis JW, Nabi IR. The lipid composition of autophagic vacuoles regulates expression of multilamellar bodies. J Cell Sci 2005; 118:1991-2003. [PMID: 15840653 DOI: 10.1242/jcs.02324] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multilamellar bodies (MLBs) are responsible for surfactant secretion in type II alveolar cells but also accumulate in other cell types under pathological conditions, including cancer and lysosomal storage diseases such as Niemann-Pick C (NPC), a congenital disease where defective cholesterol transport leads to its accumulation in lysosomes. Mv1Lu type II alveolar cells transfected with Golgi β1,6 N-acetylglucosaminyltransferase V (Mgat5), enhancing the polylactosamine content of complex-type N-glycans, exhibit stable expression of MLBs whose formation requires lysosomal proteolysis within dense autophagic vacuoles. MLBs of Mgat5-transfected Mv1Lu cells are rich in phospholipids and have low levels of cholesterol. In Mv1Lu cells treated with the NPC-mimicking drug U18666A, cholesterol-rich MLBs accumulate independently of both Mgat5 expression and lysosomal proteolysis. Inhibition of autophagy by blocking the PI 3-kinase pathway with 3-methyladenine prevents MLB formation and results in the accumulation of non-lamellar, acidic lysosomal vacuoles. Treatment with 3-methyladenine inhibited the accumulation of monodansylcadaverine, a phospholipid-specific marker for autophagic vacuoles, but did not block endocytic access to the lysosomal vacuoles. Induction of autophagy via serum starvation resulted in an increased size of cholesterol-rich MLBs. Although expression of MLBs in the Mv1Lu cell line can be induced by modulating lysosomal cholesterol or protein glycosylation, an autophagic contribution of phospholipids is critical for the formation of concentric membrane lamellae within late lysosomal organelles.
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Affiliation(s)
- Patrick Lajoie
- Department of Cellular and Physiological Sciences, University of British Columbia, 2177 Wesbrook Mall, Vancouver V6T 1Z3, British Columbia, Canada
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8
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Ridsdale R, Post M. Surfactant lipid synthesis and lamellar body formation in glycogen-laden type II cells. Am J Physiol Lung Cell Mol Physiol 2004; 287:L743-51. [PMID: 15169678 DOI: 10.1152/ajplung.00146.2004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary surfactant is a lipoprotein complex that functions to reduce surface tension at the air liquid interface in the alveolus of the mature lung. In late gestation glycogen-laden type II cells shift their metabolic program toward the synthesis of surfactant, of which phosphatidylcholine (PC) is by far the most abundant lipid. To investigate the cellular site of surfactant PC synthesis in these cells we determined the subcellular localization of two key enzymes for PC biosynthesis, fatty acid synthase (FAS) and CTP:phosphocholine cytidylyltransferase-alpha (CCT-alpha), and compared their localization with that of surfactant storage organelles, the lamellar bodies (LBs), and surfactant proteins (SPs) in fetal mouse lung. Ultrastructural analysis showed that immature and mature LBs were present within the glycogen pools of fetal type II cells. Multivesicular bodies were noted only in the cytoplasm. Immunogold electron microscopy (EM) revealed that the glycogen pools were the prominent cellular sites for FAS and CCT-alpha. Energy-filtering EM demonstrated that CCT-alpha bound to phosphorus-rich (phospholipid) structures in the glycogen. SP-B and SP-C, but not SP-A, localized predominantly to the glycogen stores. Collectively, these data suggest that the glycogen stores in fetal type II cells are a cellular site for surfactant PC synthesis and LB formation/maturation consistent with the idea that the glycogen is a unique substrate for surfactant lipids.
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Affiliation(s)
- Ross Ridsdale
- Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick Children Research Institute, and Institute of Medical Sciences, University of Toronto, Toronto, Ontario, M5G 1X8, Canada
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9
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Fehrenbach H. Alveolar epithelial type II cell: defender of the alveolus revisited. Respir Res 2001; 2:33-46. [PMID: 11686863 PMCID: PMC59567 DOI: 10.1186/rr36] [Citation(s) in RCA: 519] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2000] [Revised: 12/05/2000] [Accepted: 12/06/2000] [Indexed: 01/13/2023] Open
Abstract
In 1977, Mason and Williams developed the concept of the alveolar epithelial type II (AE2) cell as a defender of the alveolus. It is well known that AE2 cells synthesise, secrete, and recycle all components of the surfactant that regulates alveolar surface tension in mammalian lungs. AE2 cells influence extracellular surfactant transformation by regulating, for example, pH and [Ca2+] of the hypophase. AE2 cells play various roles in alveolar fluid balance, coagulation/fibrinolysis, and host defence. AE2 cells proliferate, differentiate into AE1 cells, and remove apoptotic AE2 cells by phagocytosis, thus contributing to epithelial repair. AE2 cells may act as immunoregulatory cells. AE2 cells interact with resident and mobile cells, either directly by membrane contact or indirectly via cytokines/growth factors and their receptors, thus representing an integrative unit within the alveolus. Although most data support the concept, the controversy about the character of hyperplastic AE2 cells, reported to synthesise profibrotic factors, proscribes drawing a definite conclusion today.
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Affiliation(s)
- H Fehrenbach
- Institute of Pathology, University Clinics Carl Gustav Carus, Technical University of Dresden, Germany.
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10
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Hariri M, Millane G, Guimond MP, Guay G, Dennis JW, Nabi IR. Biogenesis of multilamellar bodies via autophagy. Mol Biol Cell 2000; 11:255-68. [PMID: 10637306 PMCID: PMC14772 DOI: 10.1091/mbc.11.1.255] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Transfection of Mv1Lu mink lung type II alveolar cells with beta1-6-N-acetylglucosaminyl transferase V is associated with the expression of large lysosomal vacuoles, which are immunofluorescently labeled for the lysosomal glycoprotein lysosomal-associated membrane protein-2 and the beta1-6-branched N-glycan-specific lectin phaseolis vulgaris leucoagglutinin. By electron microscopy, the vacuoles present the morphology of multilamellar bodies (MLBs). Treatment of the cells with the lysosomal protease inhibitor leupeptin results in the progressive transformation of the MLBs into electron-dense autophagic vacuoles and eventual disappearance of MLBs after 4 d of treatment. Heterologous structures containing both membrane lamellae and peripheral electron-dense regions appear 15 h after leupeptin addition and are indicative of ongoing lysosome-MLB fusion. Leupeptin washout is associated with the formation after 24 and 48 h of single or multiple foci of lamellae within the autophagic vacuoles, which give rise to MLBs after 72 h. Treatment with 3-methyladenine, an inhibitor of autophagic sequestration, results in the significantly reduced expression of multilamellar bodies and the accumulation of inclusion bodies resembling nascent or immature autophagic vacuoles. Scrape-loaded cytoplasmic FITC-dextran is incorporated into lysosomal-associated membrane protein-2-positive MLBs, and this process is inhibited by 3-methyladenine, demonstrating that active autophagy is involved in MLB formation. Our results indicate that selective resistance to lysosomal degradation within the autophagic vacuole results in the formation of a microenvironment propicious for the formation of membrane lamella.
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Affiliation(s)
- M Hariri
- Department of Pathology and Cell Biology, University of Montreal, Montreal, Quebec, Canada H3C 3J7
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Abstract
Lamellar bodies isolated from rat lung contain all three classes of surfactant proteins, SP-A, SP-B and SP-C, as determined by immunoblot analysis. The amounts of the surfactant proteins present in lamellar bodies, determined by sandwich e.l.i.s.a. (SP-A) and fluorescamine assay (SP-B and SP-C) show that these organelles are highly enriched in the hydrophobic surfactant proteins SP-B and SP-C.
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Post M, van Golde LM. Metabolic and developmental aspects of the pulmonary surfactant system. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 947:249-86. [PMID: 3285891 DOI: 10.1016/0304-4157(88)90011-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- M Post
- Hospital for Sick Children, Division of Neonatology, Toronto, Ontario, Canada
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13
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de Vries AC, Schram AW, van den Berg M, Tager JM, Batenburg JJ, van Golde LM. An improved procedure for the isolation of lamellar bodies from human lung. Lamellar bodies free of lysosomes contain a spectrum of lysosomal-type hydrolases. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 922:259-69. [PMID: 3689811 DOI: 10.1016/0005-2760(87)90048-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We have recently shown that lamellar body fractions purified from human lung contain a distinct acid alpha-glucosidase distinguishable from lysosomal acid alpha-glucosidase in that it does not cross-react with antibodies raised against the lysosomal enzyme and does not bind to concanavalin A (De Vries, A.C.J., Schram, A.W., Tager, J.M., Batenburg, J.J. and Van Golde, L.M.G. (1985) Biochim. Biophys. Acta 837, 230-238). In order to study the relationship between the non-concanavalin A-binding alpha-glucosidase and lamellar bodies more closely a method was developed for the further purification of the organelles. A purified lamellar body preparation isolated from human lung homogenate by discontinuous sucrose density centrifugation was subjected to gel filtration with Sepharose 4B followed by Percoll density gradient centrifugation, which yielded a lamellar body preparation with a phospholipid phosphorus/protein ratio of 12.57 +/- 0.38 (mumol/mg) (n = 3) as compared to a ratio of 3.34 +/- 0.16 (mumol/mg) (n = 3) in the sucrose density gradient preparation. Concomitantly there was a 3.3 +/- 0.1 (n = 3)-fold enrichment in the content of total acid alpha-glucosidase and a 3.2 +/- 0.1 (n = 3) -fold enrichment of non-concanavalin A-binding acid alpha-glucosidase. The new purification method removes adhering proteins without changing the phospholipid composition. During the successive purification steps the concanavalin A-sensitive and -insensitive alpha-glucosidases remained fully lamellar body fraction associated. Differences between a lysosome-enriched fraction and a lamellar body preparation at varying stages of purification with respect to the ratio between soluble acid hydrolases and the membrane-associated lysosomal enzyme glucocerebrosidase indicate that the purified lamellar bodies were not contaminated with lysosomes. The absence of lysosomes in the purified lamellar body fraction was confirmed by experiments with the weak base glycyl-L-phenylalanine-beta-naphthylamide, which is an artificial substrate for the lysosomal enzyme cathepsin C and brings about lysis of lysosomes. Morphological examination by electron microscopy endorses the absence of contaminating vesicles and organelles and showed a structural integrity of the lamellar bodies in the final preparation. The improved isolation procedure strongly suggests that the concanavalin A-insensitive acid alpha-glucosidase is endogenous to lamellar bodies and supports our earlier idea that it can be used as a lamellar body-specific marker enzyme. In addition, the experiments show that lamellar bodies free of lysosomes contain a spectrum of lysosomal-type enzymes.
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Affiliation(s)
- A C de Vries
- Laboratory of Veterinary Biochemistry, Utrecht University, The Netherlands
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Lecerf J, Fouilland L, Gagniarre J. Evidence for a high activity of sphingomyelin biosynthesis by phosphocholine transfer from phosphatidylcholine to ceramides in lung lamellar bodies. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 918:48-59. [PMID: 3828366 DOI: 10.1016/0005-2760(87)90008-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Biosynthesis of sphingomyelin from ceramides was investigated in lung subcellular fractions by incubating a lyophilized mixture of albumin and subcellular fraction (0.1-0.2 mg of protein) coated with [acyl-14C]-ceramide and phosphatidyl[methyl-3H]choline in Tris-buffer. The lamellar-body-rich fraction exhibited the highest specific activity for sphingomyelin biosynthesis measured by 14C incorporation into sphingomyelins or by [3H]phosphocholine transfer from phosphatidylcholines. Plasma membranes formed the next most active fraction, followed by the 'smooth' and, then, the 'rough' endoplasmic reticulum. Sphingomyelin biosynthesis by lamellar bodies was optimum at pH 7.4 and was inhibited by sphingomyelins formed. Slight inhibitory effects were also observed with Mn2+, Ca2+ and lysophosphatidylcholine. Phosphocholine transfer from CDPcholine was not observed under the reaction conditions employed. Ceramide conversion and phosphocholine transfer increased with ceramide concentration to reach a maximum at about 0.06 mM. The highest conversion rate was observed when 18:1 ceramide was used as an acceptor. When 1-palmitoyl-2-oleoylphosphatidylcholine was the phosphocholine donor, the overall biosynthesis of sphingomyelin was much higher than when using dipalmitoylphosphatidylcholine. These results suggest the possible involvement of the studied reaction in the control of the degree of saturation of the surfactant phosphatidylcholine.
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Bourbon JR, Doucet E, Rieutort M. Role of alpha-glucosidase in fetal lung maturation. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 917:203-10. [PMID: 3539207 DOI: 10.1016/0005-2760(87)90301-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The role of lysosomal enzyme acid alpha-glucosidase in fetal lung development was investigated with the aid of a specific inhibitor, the pseudosaccharide acarbose. The drug was added to a Waymouth culture medium of fetal rat lung explants cultivated for 48 h from gestational stage 19.5 days, an in vitro system previously shown to allow morphological and biochemical maturation of alveolar epithelium. Glycogenolysis was reduced by 40% as compared with tissue cultivated on control medium, which means that alpha-glucosidase could account for as much as 40% of fetal lung glycogenolysis, the remaining 60% being presumably achieved by cytosolic phosphorylase and by a microsomal neutral alpha-glucosidase. By the same time, the increase of phospholipids of surfactant fraction extracted from cultivated explants was partially inhibited: total and saturated phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol were about 30-40% lower than in lungs cultivated on control medium. It should be emphasized that DNA concentration and increases in non-surfactant phospholipids were unchanged by the drug. alpha-Glucosidase activity was evidenced in the lysosomal fraction, in the microsomal fraction and, although in lower amounts, in the surfactant fraction extracted from term fetal lung. The results suggest that lysosomal alpha-glucosidase plays a major role in lung maturation and could facilitate glycogenolysis for the specific use of glycogen stores in providing substrates for surfactant phospholipid biosynthesis.
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de Vries AC, Schram AW, Tager JM, Batenburg JJ, van Golde LM. Genetic relationship between lysosomal and lamellar body-specific alpha-glucosidases in human lung. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 878:288-91. [PMID: 3530334 DOI: 10.1016/0005-2760(86)90159-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In lamellar bodies isolated from adult human lung at least two acid alpha-glucosidases are present: one similar to the lung lysosomal alpha-glucosidase, and another lamellar body-specific isoenzyme. In the present study we measured the activity of this lamellar body-specific alpha-glucosidase and of lysosomal alpha-glucosidase in a patient with an inherited deficiency of lysosomal alpha-glucosidase. The activity of the lamellar body-specific alpha-glucosidase was not affected in the patient, whereas the lysosomal alpha-glucosidase activity was strongly depressed. The results strongly suggest that the lysosomal alpha-glucosidase and the lamellar body-specific alpha-glucosidase are different gene products.
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