title: Lung Beractant Increases Free Cytosolic Levels of Ca2+ in Human Lung Fibroblasts.
abstract: Beractant, a natural surfactant, induces an antifibrogenic phenotype and apoptosis in normal human lung fibroblasts (NHLF). As intracellular Ca2+ signalling has been related to programmed cell death, we aimed to assess the effect of beractant on intracellular Ca2+ concentration ([Ca2+]i) in NHLF in vitro. Cultured NHLF were loaded with Fura-2 AM (3 μM) and Ca2+ signals were recorded by microfluorimetric techniques. Beractant causes a concentration-dependent increase in [Ca2+]i with a EC50 of 0.82 μg/ml. The application of beractant, at a concentration of 500 μg/ml, which has been shown to exert an apoptotic effect in human fibroblasts, elicited different patterns of Ca2+ signals in NHLF: a) a single Ca2+ spike which could be followed by b) Ca2+ oscillations, c) a sustained Ca2+ plateau or d) a sustained plateau overlapped by Ca2+ oscillations. The amplitude and pattern of Ca2+ transients evoked by beractant were dependent on the resting [Ca2+]i. Pharmacological manipulation revealed that beractant activates a Ca2+ signal through Ca2+ release from intracellular stores mediated by phospholipase Cβ (PLCβ), Ca2+ release from inositol 1,4,5-trisphosphate receptors (IP3Rs) and Ca2+ influx via a store-operated pathway. Moreover, beractant-induced Ca2+ release was abolished by preventing membrane depolarization upon removal of extracellular Na+ and Ca2+. Finally, the inhibition of store-operated channels prevented beractant-induced NHLF apoptosis and downregulation of α1(I) procollagen expression. Therefore, beractant utilizes SOCE to exert its pro-apoptotic and antifibrinogenic effect on NHLF.
authors.affiliation: Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Guzmán-Silva
authors.affiliation: Experimental Medicine Laboratory, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Luis G
authors.initials: LG
authors.lastname: Vázquez de Lara
authors.affiliation: Physiology Institute, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Julián
authors.initials: J
authors.lastname: Torres-Jácome
authors.affiliation: Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Ajelet
authors.initials: A
authors.lastname: Vargaz-Guadarrama
authors.affiliation: Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Marycruz
authors.initials: M
authors.lastname: Flores-Flores
authors.affiliation: Experimental Medicine Laboratory, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Elias
authors.initials: E
authors.lastname: Pezzat Said
authors.affiliation: Instituto Nacional de Salud Pública, Centro de Investigación sobre Enfermedades Infecciosas, Cuernavaca, Morelos, México.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Lagunas-Martínez
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México City, México.
authors.forename: Criselda
authors.initials: C
authors.lastname: Mendoza-Milla
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology ''Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Tanzi
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology ''Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Moccia
authors.affiliation: Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, México.
authors.forename: Roberto
authors.initials: R
authors.lastname: Berra-Romani
mesh_terms: D001688:Biological Products / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011663:Pulmonary Surfactants / Q000494:pharmacology*
chemical_list: D001688:Biological Products; D011663:Pulmonary Surfactants; C072197:beractant; D002118:Calcium