title: Rapidly rendering cells phagocytic through a cell surface display technique and concurrent Rac activation.
abstract: Cell surfaces represent a platform through which extracellular signals that determine diverse cellular processes, including migration, division, adhesion, and phagocytosis, are transduced. Techniques to rapidly reconfigure the surface properties of living cells should thus offer the ability to harness these cellular functions. Although the molecular mechanism of phagocytosis is well characterized, the minimal molecular players that are sufficient to activate this elaborate process remain elusive. We developed and implemented a technique to present a molecule of interest at the cell surface in an inducible manner on a time scale of minutes. We simultaneously induced the cell surface display of the C2 domain of milk fat globule epidermal growth factor factor 8 (MFG-E8) and activated the intracellular small guanosine triphosphatase Rac, which stimulates actin polymerization at the cell periphery. The C2 domain binds to phosphatidylserine, a lipid exposed on the surface of apoptotic cells. By integrating the stimulation of these two processes, we converted HeLa cells into a phagocytic cell line that bound to and engulfed apoptotic human Jurkat cells. Inducing either the cell surface display of the C2 domain or activating Rac alone was not sufficient to stimulate phagocytosis, which suggests that attachment to the target cell and actin reorganization together constitute the minimal molecular events that are needed to induce phagocytosis. This cell surface display technique might be useful as part of a targeted, cell-based therapy in which unwanted cells with characteristic surface molecules could be rapidly consumed by engineered cells.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Onuma
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan. Precursory Research for Embryonic Science and Technology Investigator, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan. tkomatsu@mol.f.u-tokyo.ac.jp jctinoue@jhmi.edu.
authors.forename: Toru
authors.initials: T
authors.lastname: Komatsu
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Arita
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Hanaoka
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
authors.forename: Tasuku
authors.initials: T
authors.lastname: Ueno
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Terai
authors.affiliation: Open Innovation Center for Drug Discovery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nagano
authors.affiliation: Precursory Research for Embryonic Science and Technology Investigator, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan. Department of Cell Biology, School of Medicine, Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA. Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA. tkomatsu@mol.f.u-tokyo.ac.jp jctinoue@jhmi.edu.
authors.forename: Takanari
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism*; D061505:Cell Surface Display Techniques / Q000379:methods*; D054338:Cell Transdifferentiation / Q000502:physiology*; D064987:Cell- and Tissue-Based Therapy / Q000379:methods; D017931:DNA Primers / Q000235:genetics; D019281:Dimerization; D005453:Fluorescence; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D008894:Milk Proteins / Q000378:metabolism*; D010587:Phagocytosis / Q000502:physiology*; D010590:Phalloidine; D010718:Phosphatidylserines / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000502:physiology; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000954:Antigens, Surface; D017931:DNA Primers; C098942:MFGE8 protein, human; D008894:Milk Proteins; D010718:Phosphatidylserines; C107953:RAC1 protein, human; D010590:Phalloidine; D020830:rac1 GTP-Binding Protein