title: Spreading of neutrophils: from activation to migration.
abstract: Neutrophils rely on rapid changes in morphology to ward off invaders. Time-resolved dynamics of spreading human neutrophils after activation by the chemoattractant fMLF (formyl methionyl leucyl phenylalanine) was observed by RICM (reflection interference contrast microscopy). An image-processing algorithm was developed to identify the changes in the overall cell shape and the zones of close contact with the substrate. We show that in the case of neutrophils, cell spreading immediately after exposure of fMLF is anisotropic and directional. The dependence of spreading area, A, of the cell as a function of time, t, shows several distinct regimes, each of which can be fitted as power laws (A ~ t(b)). The different spreading regimes correspond to distinct values of the exponent b and are related to the adhesion state of the cell. Treatment with cytochalasin-B eliminated the anisotropy in the spreading.
authors.affiliation: Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Kheya
authors.initials: K
authors.lastname: Sengupta
authors.forename: Helim
authors.initials: H
authors.lastname: Aranda-Espinoza
authors.forename: Lee
authors.initials: L
authors.lastname: Smith
authors.forename: Paul
authors.initials: P
authors.lastname: Janmey
authors.forename: Daniel
authors.initials: D
authors.lastname: Hammer
mesh_terms: D000199:Actins / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002448:Cell Adhesion; D016764:Cell Polarity; D048430:Cell Shape; D002634:Chemotaxis, Leukocyte; D003571:Cytochalasin B / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D018375:Neutrophil Activation; D009504:Neutrophils / Q000502:physiology*; D053778:Thiazolidines / Q000494:pharmacology
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D053778:Thiazolidines; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; C037067:latrunculin A