Akt activation is involved in P2Y12 receptor-mediated chemotaxis of microglia.
Microglia play a variety of significant roles in the central nervous system (CNS), and in one of those roles they undergo morphological change in response to neural injury and migrate to the injured region. We previously reported that ATP/ADP promotes microglial chemotaxis via the Gi/o-coupled P2Y12 receptor; however, the intracellular signaling underlying P2Y12-receptor-mediated microglial chemotaxis is not fully understood. In this study, we examined the role of phospholipase C (PLC) and calcium signaling in ADP-induced microglial chemotaxis. A PLC inhibitor, U73122, significantly suppressed the chemotaxis and completely blocked the ADP-evoked intracellular calcium response, and a calcium chelator, BAPTA-AM, inhibited the chemotaxis. These results indicate that ADP-induced microglial chemotaxis is regulated by a PLC-mediated calcium pathway. ADP stimulation induced Akt phosphorylation in microglia, and the phosphorylation was inhibited by a P2Y12 receptor antagonist, AR-C69931MX. The Akt phosphorylation was blocked by U73122 and BAPTA-AM as well as by a phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin, and inhibition of the Akt activation resulted in failure of chemotaxis. These results indicate that Akt activation is dependent on the PI3K pathway and a PLC-mediated increase in intracellular calcium and suggest that Akt activation is involved in ADP-induced microglial chemotaxis.
Irino
Yasuhiro
Y
Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan.
Nakamura
Yasuko
Y
Inoue
Kazuhide
K
Kohsaka
Shinichi
S
Ohsawa
Keiko
K
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008565:Membrane Proteins / Q000502:physiology*; D017628:Microglia / Q000187:drug effects / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D058925:Receptors, Purinergic P2Y12; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D010738:Type C Phospholipases / Q000378:metabolism
D004791:Enzyme Inhibitors; D008565:Membrane Proteins; C553058:P2ry12 protein, rat; D018048:Receptors, Purinergic P2; D058925:Receptors, Purinergic P2Y12; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; C117446:cangrelor; D000255:Adenosine Triphosphate; D051057:Proto-Oncogene Proteins c-akt; D010738:Type C Phospholipases; D002118:Calcium