title: Potential effects of microglial activation induced by ginsenoside Rg3 in rat primary culture: enhancement of type A Macrophage Scavenger Receptor expression.
abstract: Brain microglia are phagocytic cells that are the major inflammatory response cells of the central nervous system and widely held to play important pathophysiologic roles in Alzheimer's disease (AD) in both potentially neurotoxic responses and potentially beneficial phagocytic responses. In the study, we examined whether ginsonoside Rg3, a by-product of red ginseng, enhances the microglial phagocytosis of Abeta. We found that Rg3 promoted Abeta uptake, internalization, and digestion. Increased maximal Abeta uptake was observed at 4 and 8 h after Rg3 pre-treatment (25 microg/mL), and the internalized Abeta was almost completely digested from cells within 36 h when pretreated with Rg3 comparing with single non-Rg3-treated groups. The expression of MSRA (type A MSR) was also up-regulated by Rg3 treatment in a dose- and time-dependent manner which was coincidently identified in western blots for MSRA proteins in cytosol. These results indicate that microglial phagocytosis of Abeta may be enhanced by Rg3 and the effect of Rg3 on promoting clearance of Abeta may be related to the MSRA-associated action of Rg3. Thus, stimulation of the MSRA might contribute to the therapeutic potentials of Rg3 in microglial phagocytosis and digestion in the treatment of AD.
authors.affiliation: Department of Immunology, College of Pharmacy, Chung-Ang University, Seoul, Korea.
authors.forename: Seong Soo
authors.initials: SS
authors.lastname: Joo
authors.forename: Do Ik
authors.initials: DI
authors.lastname: Lee
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000493:pharmacokinetics; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002232:Carbocyanines / Q000737:chemistry; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000737:chemistry; D015870:Gene Expression / Q000187:drug effects; D036145:Ginsenosides / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000737:chemistry / Q000493:pharmacokinetics; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010446:Peptide Fragments / Q000737:chemistry / Q000493:pharmacokinetics; D010587:Phagocytosis / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051116:Receptors, Scavenger / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D016229:Amyloid beta-Peptides; D002232:Carbocyanines; D005456:Fluorescent Dyes; D036145:Ginsenosides; D008077:Lipoproteins, LDL; D010446:Peptide Fragments; D012333:RNA, Messenger; D051116:Receptors, Scavenger; C032629:acetyl-LDL; C075222:amyloid beta-protein (1-42); C089187:cyanine dye 3; C097367:ginsenoside Rg3; C024286:3,3'-dioctadecylindocarbocyanine