title: Matrix confinement plays a pivotal role in regulating neutrophil-generated tractions, speed, and integrin utilization.
abstract: Neutrophils are capable of switching from integrin-dependent motility on two-dimensional substrata to integrin-independent motion following entry into the confined three-dimensional matrix of an afflicted tissue. However, whether integrins still maintain a regulatory role for cell traction generation and cell locomotion under the physical confinement of the three-dimensional matrix is unknown, and this is challenging to deduce from motility studies alone. Using three-dimensional traction force microscopy and a double hydrogel sandwich system, we determined the three-dimensional spatiotemporal traction forces of motile neutrophils at unprecedented resolution and show, for the first time, that entry into a highly confined space (2.5D) is a sufficient trigger to convert to integrin-independent migration. We find that integrins exert a significant regulatory role in determining the magnitude and spatial distribution of tractions and cell speed on confined cells. We also find that 90% of neutrophil tractions are in the out-of-plane axis, and this may be a fundamental element of neutrophil traction force generation.
authors.affiliation: From the School of Engineering, Brown University, Providence, Rhode Island 02912 and.
authors.forename: Jennet
authors.initials: J
authors.lastname: Toyjanova
authors.affiliation: the Department of Surgery, Rhode Island Hospital/Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903.
authors.forename: Estefany
authors.initials: E
authors.lastname: Flores-Cortez
authors.affiliation: the Department of Surgery, Rhode Island Hospital/Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Reichner
authors.affiliation: From the School of Engineering, Brown University, Providence, Rhode Island 02912 and franck@brown.edu.
authors.forename: Christian
authors.initials: C
authors.lastname: Franck
mesh_terms: D002448:Cell Adhesion; D002465:Cell Movement; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology; D016023:Integrins / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
chemical_list: D016023:Integrins; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
keywords: Cell Motility; Confocal Microscopy; Integrin; Leukocyte; Neutrophil