Effect of combination of residual glucose concentration and subsequent increment by temporal glucose feeding on oscillation of clock gene Per2 expression.

With the aim of regulating clock gene expression to control cell activities in cell processing engineering, the effect of the combination of residual glucose concentration and subsequent increment by temporal glucose feeding on the oscillation of the expression of clock gene Per2 was investigated employing rat Mesenchymal stem cell (MSC)-like cells having Per2 promoter gene with a destabilized luciferase gene (Per2-dLuc). Two experiments with several initial glucose concentrations and different times of cultures (2 and 5 days) before temporal glucose feeding (0.9 g/L) were employed to realize various concentrations of residual glucose in the medium before the feeding. In these experiments, the lower residual glucose concentrations (0.002-0.02 g/L) before temporal glucose feeding tended to induce the larger amplitude of oscillation of Per2 expression than the higher ones (0.55-0.74 g/L). When the residual glucose concentration before glucose feeding was low (0.014-0.038 g/L), the higher temporal glucose concentration (0.23-0.9 g/L) feeding tended to induce the larger amplitude of oscillation of Per2 expression than the lower ones (0.012-0.023 g/L). Taken together, we found that the amplitude of oscillation of the expression of clock gene Per2 could be controlled by the combination of residual glucose concentration and glucose concentration of subsequent temporal feeding.