title: Spectral phasor analysis of LAURDAN fluorescence in live A549 lung cells to study the hydration and time evolution of intracellular lamellar body-like structures.
abstract: Using LAURDAN spectral imaging and spectral phasor analysis we concurrently studied the growth and hydration state of subcellular organelles (lamellar body-like, LB-like) from live A549 lung cancer cells at different post-confluence days. Our results reveal a time dependent two-step process governing the size and hydration of these intracellular LB-like structures. Specifically, a first step (days 1 to 7) is characterized by an increase in their size, followed by a second one (days 7 to 14) where the organelles display a decrease in their global hydration properties. Interestingly, our results also show that their hydration properties significantly differ from those observed in well-characterized artificial lamellar model membranes, challenging the notion that a pure lamellar membrane organization is present in these organelles at intracellular conditions. Finally, these LB-like structures show a significant increase in their hydration state upon secretion, suggesting a relevant role of entropy during this process.
authors.affiliation: Área de Investigación Respiratoria, Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Uruguay; Unidad de Bioquímica y Proteómica Analítica, Institut Pasteur de Montevideo, Uruguay; Laboratory for Fluorescence Dynamics, Biomedical Engineering Department, University of California at Irvine, Irvine, CA, USA. Electronic address: lmalacrida@hc.edu.uy.
authors.forename: Leonel
authors.initials: L
authors.lastname: Malacrida
authors.affiliation: Unidad de Biología Celular, Institut Pasteur de Montevideo, Uruguay.
authors.forename: Soledad
authors.initials: S
authors.lastname: Astrada
authors.affiliation: Área de Investigación Respiratoria, Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Uruguay.
authors.forename: Arturo
authors.initials: A
authors.lastname: Briva
authors.affiliation: Unidad de Biología Celular, Institut Pasteur de Montevideo, Uruguay.
authors.forename: Mariela
authors.initials: M
authors.lastname: Bollati-Fogolín
authors.affiliation: Laboratory for Fluorescence Dynamics, Biomedical Engineering Department, University of California at Irvine, Irvine, CA, USA.
authors.forename: Enrico
authors.initials: E
authors.lastname: Gratton
authors.affiliation: MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, Odense M, Denmark. Electronic address: bagatolli@memphys.sdu.dk.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Bagatolli
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives* / Q000737:chemistry; D000072283:A549 Cells; D001692:Biological Transport; D019277:Entropy; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D007848:Laurates / Q000737:chemistry*; D053141:Organelle Size; D015388:Organelles / Q000378:metabolism* / Q000648:ultrastructure; D009994:Osmolar Concentration; D013050:Spectrometry, Fluorescence; D014867:Water / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D007848:Laurates; D014867:Water; D015081:2-Naphthylamine; C065580:laurdan
keywords: LAURDAN; Lamellar bodies; Macromolecular crowding; Membrane biophysics; Microscopic imaging; Spectral phasor