Cytokine release by murine spleen cells following multiple low dose streptozotocin-induced diabetes and treatment with a TNFα transcriptional inhibitor

Abstract

We recently reported that administration of 9-[(1 R, 3 R)- trans-cyclopentan-3-ol] adenine (MDL 201,449A), a transcriptional inhibitor of TNFα, decreased hyperglycemia in murine diabetes induced by multiple low doses of streptozotocin (MLDSTZ). In the present study, we first investigated if in vivo administration of MDL 201,449A in the MLDSTZ model affects cytokine release from cultured spleen cells. Secondly, we studied how MDL 201,449A affects cytokine release from normal cultured spleen cells. In all experiments, the mitogen concanavalin A (2 μg/ml) was added to the cultured spleen cells in order to enhance cytokine release. MLDSTZ treatment in vivo caused increased IFNγ secretion, a decreased/retarded rate of increased TNFα accumulation, whereas IL-10 production was not altered compared to vehicle-treated mice. MDL 201,449A treatment of MLDSTZ mice did not affect cytokine release from spleen cells subsequently cultured in the absence of MDL 201,449A. We also studied cytokine release from normal spleen cells in the presence or absence of MDL 201,449A. Production of TNFα, IFNγ and IL-10 was all suppressed by the drug. In groups where exposure to MDL 201,449A was discontinued, cytokine levels increased promptly and in the case of TNFα secretion, it exceeded the production from control cells. Our data suggest an enhanced Th1 cytokine secretion from spleen cells derived from MLDSTZ-treated mice. MDL 210,449A may be a potent inhibitor of cytokine secretion, albeit not completely selective for TNFα. However, when MDL 201,449A is withdrawn, there may be a rebound phenomenon of increased TNFα secretion.