title: P2X7 receptors regulate engulfing activity of non-stimulated resting astrocytes.
abstract: We previously demonstrated that P2X7 receptors (P2X7Rs) expressed by cultured mouse astrocytes were activated without any exogenous stimuli, but its roles in non-stimulated resting astrocytes remained unknown. It has been reported that astrocytes exhibit engulfing activity, and that the basal activity of P2X7Rs regulates the phagocytic activity of macrophages. In this study, therefore, we investigated whether P2X7Rs regulate the engulfing activity of mouse astrocytes. Uptake of non-opsonized beads by resting astrocytes derived from ddY-mouse cortex time-dependently increased, and the uptaken beads were detected in the intracellular space. The bead uptake was inhibited by cytochalasin D (CytD), an F-actin polymerization inhibitor, and agonists and antagonists of P2X7Rs apparently decreased the uptake. Spontaneous YO-PRO-1 uptake by ddY-mouse astrocytes was reduced by the agonists and antagonists of P2X7Rs, but not by CytD. Down-regulation of P2X7Rs using siRNA decreased the bead uptake by ddY-mouse astrocytes. In addition, compared to in the case of ddY-mouse astrocytes, SJL-mouse astrocytes exhibited higher YO-PRO-1 uptake activity, and their bead uptake was significantly greater. These findings suggest that resting astrocytes exhibit engulfing activity and that the activity is regulated, at least in part, by their P2X7Rs.
authors: Department of Environmental Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors: Mina
authors: M
authors: Yamamoto
authors: Yosuke
authors: Y
authors: Kamatsuka
authors: Akihiro
authors: A
authors: Ohishi
authors: Kentaro
authors: K
authors: Nishida
authors: Kazuki
authors: K
authors: Nagasawa
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D001583:Benzoxazoles / Q000493:pharmacokinetics; D002470:Cell Survival; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D015638:Cytochalasin D / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D005786:Gene Expression Regulation; D051379:Mice; D009474:Neurons / Q000378:metabolism; D010587:Phagocytosis; D011806:Quinolinium Compounds / Q000493:pharmacokinetics; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism*
chemical_list: D001583:Benzoxazoles; D005456:Fluorescent Dyes; D011806:Quinolinium Compounds; D058486:Receptors, Purinergic P2X7; C089813:YO-PRO 1; D015638:Cytochalasin D; D000255:Adenosine Triphosphate
keywords: Astrocyte; Engulfing activity; P2X7 receptor