Constitutive and functional expression of runt-related transcription factor-2 by microglial cells.
Runt-related transcription factor-2 (Runx2) is the master regulator of osteoblastogenesis with an ability to promote differentiation of mesenchymal stem cells into the osteoblastic lineage. We have previously shown constitutive and functional expression of Runx2 by astroglial cells. In this study, we investigated the possible expression of Runx2 by both murine microglia and microglial cell line BV-2 cells. Runx2 expression was seen in cultured microglia and BV-2 cells, while sustained exposure to 1mM ATP led to a significant but transient increase in mRNA and corresponding protein expression of Runx2 within 24 h. The increase in Runx2 expression was invariably prevented by several chemicals with antagonistic properties for P2X7 purinergic receptor, calmodulin and calcineurin in BV-2 cells, with a P2X7 receptor agonist more than quadrupling Runx2 expression. A significant increase in Runx2 expression was seen in osteoclastic cells, but not in osteoblastic or chondrocytic cells, when exposed to a high concentration of ATP. In BV2-cells with control siRNA, a significant decrease was found in the number of cells with at least one process within 3 h after the exposure to 1mM ATP, followed by an increase up to 24 h. However, Runx2 siRNA significantly deteriorated the property to induce delayed process extension during 6-24 h after exposure to ATP along with drastically decreased Runx2 protein levels. These results suggest that Runx2 is constitutively and functionally expressed by microglial cells with responsiveness to ATP for upregulation in the murine brain.
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan.
Ryota
R
Nakazato
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan.
Takeshi
T
Takarada
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan.
Takumi
T
Watanabe
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan.
Binh Thanh
BT
Nguyen
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan.
Shinsuke
S
Ikeno
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan.
Eiichi
E
Hinoi
Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan. Electronic address: yyoneda@p.kanazawa-u.ac.jp.
Yukio
Y
Yoneda
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D005260:Female; D008297:Male; D051379:Mice; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism
D050659:Core Binding Factor Alpha 1 Subunit; D017931:DNA Primers; D012333:RNA, Messenger; D058486:Receptors, Purinergic P2X7; C493716:Runx2 protein, mouse; D000255:Adenosine Triphosphate
ATP; BV-2 cells; Calcium; Microglia; P2X7 receptor; Runx2