Lamellar Bodies Form Solid Three-dimensional Films at the Respiratory Air-Liquid Interface |
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Authors: | Andrea Ravasio Bárbara Olmeda Cristina Bertocchi Thomas Haller Jesús Pérez-Gil |
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Institution: | From the Departments of ‡Physiology and Medical Physics and ;¶Internal Medicine I, Innsbruck Medical University, 6020 Innsbruck, Austria and ;the §Departamento de Bioquímica, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain |
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Abstract: | Pulmonary surfactant is essential for lung function. It is assembled, stored and secreted as particulate entities (lamellar body-like particles; LBPs). LBPs disintegrate when they contact an air-liquid interface, leading to an instantaneous spreading of material and a decline in surface tension. Here, we demonstrate that the film formed by the adsorbed material spontaneously segregate into distinct ordered and disordered lipid phase regions under unprecedented near-physiological conditions and, unlike natural surfactant purified from bronchoalveolar lavages, dynamically reorganized into highly viscous multilayer domains with complex three-dimensional topographies. Multilayer domains, in coexistence with liquid phases, showed a progressive stiffening and finally solidification, probably driven by a self-driven disassembly of LBPs from a sub-surface compartment. We conclude that surface film formation from LBPs is a highly dynamic and complex process, leading to a more elaborated scenario than that observed and predicted by models using reconstituted, lavaged, or fractionated preparations. |
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Keywords: | Lipid Absorption Lung Membrane Biophysics Membrane Fusion Pulmonary Surfactant Air-Liquid Interface Lamellar Bodies Surface Tension |
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