Figure 5.

Induction of pro-inflammatory cytokines in brain-penetrant macrophages and resident microglia is eliminated by reinstating BBB integrity. (a) Protein array analysis of conditioned media from forebrain mononuclear cells (FMCs) isolated from vehicle-treated db/db and Wt mice (db/Veh, Wt/Veh) and from db/db mice administered the PKCβ inhibitor Enzastaurin (db/Enz). Graphs represent data from db/Veh and db/Enz cells, with each target normalized to the corresponding mean intensity in samples from Wt/Veh cells. FMCs from db/Veh mice released significantly more interleukin 1β (IL1β), interleukin 6 (IL6), monocyte chemoattractant protein 1 (MCP1) and tumor necrosis factor-α (TNFα), but induction of these pro-inflammatory cytokines was not detected in cells from db/Enz mice. (b) Quantification of interleukin 1β (IL1β) by western blotting in cell lysates revealed increased IL1β in db/Veh cells, but not in db/Enz cells. (c) Reinstatement of BBB integrity in db/Enz mice reduced levels of IL6 in cell lysates. (d) FMCs from db/Veh mice, but not db/Enz mice, exhibit increases in MCP1 protein. (e) PKCβ antagonism prevents increases in TNFα in cell lysates from db/db mice. For all graphs, bar height depicts the mean fold change from Wt/Veh (A) or the group mean (B-E) from (n = 6) mice per condition. Error bars represent the SEM and asterisks (*) denote statistical significance at p < 0.05 following one-way ANOVA with Bonferonni’s post hoc.