Dynamics of actin filaments in microglia during Fc receptor-mediated phagocytosis.
The phagocytic ability of mouse microglia during their differentiation in culture and after stimulation with bacterial wall lipopolysaccharide (LPS) has been investigated using Fc receptor-mediated phagocytosis of immunoglobulin (IgG)-coated sheep erythrocytes (SRBCs). We observed that in 10-14 day-confluent neopallial cell cultures some immature microglia are not phagocytic but, on further culturing, they do become phagocytic. LPS-stimulated microglia are able to phagocytose larger numbers of IgG-coated SRBCs and at a faster rate than non-stimulated microglia. Within 5-10 min of phagocytosis the actin filaments of the LPS-stimulated microglia become depolymerized, leaving only bundles of actin filaments around the phagocytosed SRBCs (phagosome cups). At 30 min after the start of phagocytosis the actin filaments of the LPS-stimulated microglia begin to polymerize, and within 2 h the original pre-phagocytosis pattern of the actin filament network is re-established. The non-LPS-stimulated microglia exhibit actin filament depolymerization in only a few lamellipodia and polymerization of actin filaments around engulfed particles, but much later during phagocytosis.
Abd-el-Basset
E M
EM
Department of Anatomy, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Fedoroff
S
S
D000199:Actins / Q000378:metabolism*; D000818:Animals; D004912:Erythrocytes / Q000502:physiology*; D007074:Immunoglobulin G / Q000502:physiology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D017628:Microglia / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D010587:Phagocytosis; D011961:Receptors, Fc / Q000502:physiology*
D000199:Actins; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D011961:Receptors, Fc