Premium
Differential activation of subtype purinergic receptors modulates Ca 2+ mobilization and COX‐2 in human microglia
Author(s) -
Choi Hyun B.,
Hong Seok H.,
Ryu Jae K.,
Kim Seung U.,
McLar James G.
Publication year - 2003
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.10239
Subject(s) - ppads , purinergic receptor , microglia , biology , adenosine , receptor , purinergic signalling , medicine , endocrinology , p2y receptor , neuroglia , adenosine triphosphate , agonist , adenosine receptor , biochemistry , immunology , central nervous system , inflammation
We have studied modulation of purinergic receptors (P 2Y and P 2X subtypes) on changes in intracellular Ca 2+ [Ca 2+ ] i and expression and production of COX‐2 in human microglia. Measurements using Ca 2+ ‐sensitive spectrofluorometry showed adenosine triphosphate (ATP) to cause rapid transient increases in [Ca 2+ ] i . Application of ATP plus the P 2X antagonist, pyridoxal‐phosphate‐6‐azophenyl‐2′,4′‐disulfonic acid (PPADS), or treatment with adenosine diphosphate‐β‐S (ADP‐β‐S), a selective P 2Y agonist, led to a considerable prolongation in [Ca 2+ ] i responses compared with ATP. The prolonged time courses were consistent with sustained activation of store‐operated channels (SOC) since SKF96365, an inhibitor of SOC, blocked this component of the response. RT‐PCR data showed that microglia expressed no COX‐2 either constitutively or following treatment of cells with ATP (100 μM for 8 h). However, treatment using ATP plus PPADS or with ADP‐β‐S led to marked expression of COX‐2. The enhanced COX‐2 with ATP plus PPADS treatment was absent in the presence of SKF96365 or using Ca 2+ ‐free solution. Immunocytochemistry, using a specific anti‐COX‐2 antibody, also revealed a pattern of purinergic modulation whereby lack of P 2X activation enhanced the production of COX‐2 protein. These results suggest that modulation of subtypes of purinergic receptors regulates COX‐2 in human microglia with a link involving SOC‐mediated influx of Ca 2+ . © 2003 Wiley‐Liss, Inc.