ATP-stimulated interleukin-6 synthesis through P2Y receptors on human osteoblasts.
We investigated the effect of extracellular adenosine triphosphate (ATP) on the production of interleukin (IL)-6, whose molecules are capable of stimulating the development of osteoclasts from their hematopoietic precursors as well as are involved in signal transduction systems in human osteoblastic SaM-1 cells. These human osteoblasts constitutively expressed P2X4, P2X5, P2X6, P2Y2, P2Y5, and P2Y6 purinergic receptors. ATP increased gene- and protein-expression of IL-6 in SaM-1 cells. The expression of the IL-6 mRNA was maximal at 1h, and the increase in IL-6 synthesis in response to ATP (10-100 microM) occurred in a concentration-dependent manner. Over the same concentration range of the nucleotide that was effective for IL-6 synthesis, ATP caused an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)), which increase was inhibited by pretreatment with suramin, a P2Y receptor antagonist, or 2-aminoethoxydiphenyl borate (2-APB), an inositol 1,4,5-trisphosphate receptor blocker, but not by the extracellular Ca(2+)-chelating agent EGTA. The pretreatment of SaM-1 cells with suramin or 2-APB also inhibited the increase in IL-6 synthesis in response to ATP. These findings suggest that extracellular ATP-induced IL-6 synthesis occurs through P2Y receptors and mobilization of Ca(2+) from internal stores in human osteoblastic cells.
Ihara
Hiroyuki
H
Department of Pharmacology, School of Dentistry, Aichi-Gakuin University, Nagoya 464-8650, Japan.
Hirukawa
Koji
K
Goto
Shigemi
S
Togari
Akifumi
A
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics*; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*
D015850:Interleukin-6; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D002118:Calcium