Effect of Ca2+ ATPase Inhibitors on MCP-1 Release from Bone Marrow-Derived Mast Cells and the Involvement of p38 MAP Kinase Activation

Abstract

The effect of two Ca²⁺ ATPase inhibitors, cyclopiazonic acid (CPA) and 2,5-di-(tert-butyl)-1,4-hydroquinone (DTBHQ), on the release of MCP-1 from bone marrow-derived mast cells (BMMCs) were investigated. CPA and DTBHQ increased the intracellular free Ca²⁺ concentration ([Ca²⁺]_i) and induced MCP-1 release in a dose-dependent manner. These Ca²⁺ ATPase inhibitors induced MCP-1 release in the absence of phorbol ester, in contrast to their induction of TNF-α. MCP-1 release reached a maximum at 6–9 h. It was inhibited by treatment with actinomycin D, the immunosuppressant cyclosporin A, and the cytosolic Ca²⁺ chelator BAPTA-AM. Furthermore, RT-PCR showed a time-dependent increase of MCP-1 mRNA. Thus MCP-1 release seems to depend on Ca²⁺-dependent transcriptional activation. MCP-1 release was dose-dependently inhibited by the p38 MAP kinase inhibitor SB202190, but not by the p44/42 MAP kinase inhibitor PD98059. Therefore, transcriptional activation of MCP-1 production and its release seem to be dependent on the nuclear factor of activated T cells and p38 MAP kinase activation. This is the first report to show the regulation of MCP-1 production in BMMCs.