title: Surface tension influences cell shape and phagocytosis in alveolar macrophages.
abstract: The effect of surface tension on alveolar macrophage shape and phagocytosis was assessed in vivo and in vitro. Surface tension was regulated in vivo by conditionally expressing surfactant protein (SP)-B in Sftpb-/- mice. Increased surface tension and respiratory distress were produced by depletion of SP-B and were readily reversed by repletion of SP-B in vivo. Electron microscopy was used to demonstrate that alveolar macrophages were usually located beneath the surfactant film on the alveolar surfaces. Reduction of SP-B increased surface tension and resulted in flattening of alveolar macrophages on epithelial surfaces in vivo. Phagocytosis of intratracheally injected fluorescent microbeads by alveolar macrophages was decreased during SP-B deficiency and was restored by repletion of SP-B in vivo. Incubation of MH-S cells, a mouse macrophage cell line, with inactive surfactant caused cell flattening and decreased phagocytosis in vitro, findings that were reversed by the addition of sheep surfactant or phospholipid containing SP-B. SP-B controls surface tension by forming a surfactant phospholipid film that regulates shape and nonspecific phagocytic activity of alveolar macrophages on the alveolar surface.
authors.affiliation: Cincinnati Children's Hospital, Division of Pulmonary Biology, University of Cincinnati, OH 45229-3039, USA.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Akei
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Whitsett
authors.forename: Michelle
authors.initials: M
authors.lastname: Buroker
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ninomiya
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Tatsumi
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Weaver
authors.forename: Machiko
authors.initials: M
authors.lastname: Ikegami
mesh_terms: D000818:Animals; D048430:Cell Shape; D002478:Cells, Cultured; D005453:Fluorescence; D016676:Macrophages, Alveolar / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D008863:Microspheres; D010587:Phagocytosis; D037701:Pulmonary Surfactant-Associated Protein B / Q000172:deficiency* / Q000494:pharmacology; D012120:Respiration Disorders / Q000209:etiology / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D013500:Surface Tension
chemical_list: D037701:Pulmonary Surfactant-Associated Protein B