Cell Type-Specific Dependency on the PI3K/Akt Signaling Pathway for the Endogenous Epo and VEGF Induction by Baicalein in Neurons versus Astrocytes
Figure 1
Effects of baicalein on the HIF1α activity and expression of Epo and VEGF in cortical neurons.
(A) Primary cultured cortical neurons co-transfected with pHREEPO-Luc and pRL-TK were treated with baicalein (BA) at indicated concentrations (3.5 nM~35 μM) or CoCl2 (0.4 mM) for luciferase activity assay of HRE-driven gene expression as an index of HIF activity. Inset in A: EC50 of BA on HREEPO-driven luciferase. (B) qRT-PCR of Epo and VEGF mRNA of RNA extracted BA-treated neurons at indicated time or concentrations. (C) Upper panel: RT-PCR analysis of HIF1α mRNA in neurons transfected with scrambled RNA (Scr) or siHif1a. Lower panel: qRT-PCR analysis of Epo and VEGF mRNA in 3.5 μM BA-treated neurons transfected with Scr or siHif1a. (D) ELISA of Epo and VEGF of cell lysate of BA-treated neurons. Data represent means ± SEM (n=3). *p<0.05, **p<0.01 and ***p<0.001 versus vehicle-treated control by one-way ANOVA and Newman-Keuls multiple comparison posttest; # p<0.05 and # # # p<0.001 versus the Scr-Ctrl by unpaired t-test.