title: Probing the endocytic pathways of the filamentous bacteriophage in live cells using ratiometric pH fluorescent indicator.
abstract: Viral nanoparticles have attracted extensive research interests in diverse applications of diagnosis and therapy. In particular, filamentous M13 bacteriophages have shown great potential in biomedical applications. However, its pathways entering into cells still remain unclear, and this greatly hinders its further use as a drug or gene carrier. Here, a ratiometric M13 pH probe is designed by conjugating two fluorescent dyes onto the surface of M13. Since the intensity ratio is not influenced by probe concentration, ion strength, temperature, photobleaching, and optical path length, this ratiometric probe can be used to investigate the intracellular pH map of M13. More importantly, the internalization mechanism of M13 can be elucidated. It is found that this filamentous phage shows great cell-type dependence in interaction with cells and internalization mechanism. The phage tends to be bounded on the cell membrane of only epithelial cells, not endothelial cells. Furthermore, the M13 phage enters into cells through endocytosis with specific mechanism: clathrin-mediated endocytosis and macropinocytosis for HeLa; vesicular transport, clathrin-mediated endocytosis, and macropinocytosis for MCF-7; caveolae-mediated endocytosis for human dermal microvascular endothelial cell (HDMEC). This work provides key notes for cancer diagnosis and therapy based on filamentous bacteriophage, especially for design of pH-sensitive drug delivery systems.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 29 Zhongguancun East Road, Beijing, 100190, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.forename: Man
authors.initials: M
authors.lastname: Wu
authors.forename: Xiangxiang
authors.initials: X
authors.lastname: Liu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhou
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Niu
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
mesh_terms: D017104:Bacteriophage M13 / Q000737:chemistry* / Q000378:metabolism; D001671:Biochemistry / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004705:Endocytosis; D019793:Fluorescein / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D061986:MCF-7 Cells / Q000187:drug effects; D057054:Molecular Imaging / Q000379:methods; D012235:Rhodamines / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D012235:Rhodamines; C029773:rhodamine B; D019793:Fluorescein
keywords: M13 bacteriophage; endocytosis; intracellular pH probe; pharmacological inhibitors; ratiometric