Role of lipid rafts in phagocytic uptake of polystyrene latex microspheres by macrophages.
BACKGROUND
Micro- and nanospheres have been used as carrier materials for effective delivery of drugs into macrophages via endocytosis including phagocytosis for the treatment of cancer and infections.


METHODS
To analyze the role of lipid rafts in the endocytic uptake of microspheres by macrophages, we studied the incorporation of polystyrene latex microspheres (PSL MS) by treating macrophages with reagents that affect the physicochemical and biochemical functions of their lipid rafts, such as the cholesterol depletor methyl-β-cyclodextrin (MβCD) and the inhibitor of scavenger receptors polyinosinic acid (poly I). For this study, we used 3-μm fluorescent polystyrene latex microspheres (F-PSL MS) and J774 murine macrophage.


RESULTS
We found that the endocytosis of J774 cells was remarkably reduced in a concentration-dependent manner by treatment of the cells with MβCD and that endocytosis was suppressed by approximately 50% by treatment with 100 μg/ml poly I. These results suggest that scavenger receptors are associated with phagocytosis of F-PSL MS and that their functions are regulated by lipid rafts.


CONCLUSIONS
PSL MS are phagocytosed via a raft-dependent pathway.
Nagao
Goshi
G
Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba 278-8510, Japan.
Ishii
Kazuo
K
Hirota
Keiji
K
Makino
Kimiko
K
Terada
Hiroshi
H
D000818:Animals; D002460:Cell Line; D004705:Endocytosis; D007840:Latex / Q000378:metabolism*; D050356:Lipid Metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008863:Microspheres; D010587:Phagocytosis; D011137:Polystyrenes / Q000378:metabolism*
D007840:Latex; D011137:Polystyrenes