title: Can phage display be used as a tool to functionally identify endogenous eat-me signals in phagocytosis?
abstract: Removal of apoptotic cells and cellular debris by phagocytosis is essential for development, tissue homeostasis, and resolution of inflammation. Eat-me signals control the initiation of phagocytosis, holding a key to the understanding of phagocyte biology. Because of a lack of functional cloning strategy, eat-me signals are conventionally identified and characterized on a case-by-case basis. The feasibility of functional cloning of eat-me signals by phage display is investigated by characterizing the biological behavior of T7 phages displaying 2 well-known eat-me signals: growth arrest-specific gene 6 (Gas6) and milk fat globule-EGF8 (MFG-E8). Gas6-phage binds to all 3 known Gas6 receptors: Mer, Axl, and Tyro3 receptor tyrosine kinases. Gas6-phage and MFG-E8-phage are capable of binding to phagocytes and nonphagocytes. However, both phages stimulate phage uptake only in phagocytes, including macrophages, microglia, and retinal pigment epithelium cells, but not in nonphagocytes. Furthermore, functional phage selection by phagocytosis in phagocytes enriches both Gas6-phage and MFG-E8-phage, suggesting that phage display can be used as a tool to functionally identify unknown eat-me signals from phage display cDNA library.
authors.affiliation: Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami School of Medicine, Miami, Florida 33136, USA.
authors.forename: Nora B
authors.initials: NB
authors.lastname: Caberoy
authors.forename: Yixiong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D017123:Bacteriophage T7 / Q000235:genetics; D002460:Cell Line; D005822:Genetic Vectors; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D019151:Peptide Library; D010586:Phagocytes / Q000378:metabolism; D010587:Phagocytosis / Q000502:physiology*; D015398:Signal Transduction; D019809:Streptavidin / Q000378:metabolism; D000099255:Growth Arrest-Specific Protein 6
chemical_list: D000954:Antigens, Surface; D055767:Immobilized Proteins; D036341:Intercellular Signaling Peptides and Proteins; D019151:Peptide Library; D019809:Streptavidin; D000099255:Growth Arrest-Specific Protein 6