Figure 2

Histidine appears to act by inhibiting the ATX LPLD activity. The modified Boyden chamber motility assays with A2058 cells are described in Materials and Methods. In these assays, pre-incubations were in DBA media for 3 hr at 37°C. A) L-histidine decreases formation of a chemoattractant by ATX. Shown concentrations of L-histidine were pre-incubated with ATX plus 200 nM LPC, then ATX was heat-inactivated prior to utilizing the resulting mixture as chemoattractant in a motility assay (solid black bars). Data are compared to identical treatments of 100 nM LPA as chemoattractant (white bars). B.) L-histidine decreases formation of a motility inhibitor by ATX. Shown concentrations of L-histidine were pre-incubated with (ATX + 100 nM SPC + 100 nM LPA). ATX was heat inactivated prior to utilizing the mixture as chemoattractant. Controls are shown for comparison: DBA, 100 nM LPA, (100 nM LPA + 100 nM S1P), (100 nM LPA + 100 nM SPC). All data are shown as Mean ± SEM. Means were analyzed utilizing the ANOVA/Tukey's post-test (GraphPad Prism, San Diego, CA): * (p < 0.001) for histidine-treated vs. the appropriate untreated control.