Post-injury administration of SB-216763 improves motor function.

<p><b>A</b>) Schematic of the drug injection and behavioral testing paradigm. Rats (n = 10/group) were injected (i.p.) for the first 5 days post-injury with either 5.0 mg/kg SB-216763 or vehicle. SB-216763-treated rats had <b>B</b>) comparable vestibulomotor deficits, but made significantly fewer <b>C</b>) ipsilateral and <b>D</b>) contralateral foot faults. <b>E</b>) Body weight was unaffected by SB-216763 administration. Data are presented as the mean ± SEM. ‡, P<0.05 by two-way repeated measures ANOVA.</p

Systemic lithium administration inhibits hippocampal GSK-3 activity.

<p><b>A</b>) Representative western blots showing the dose response of different amounts of lithium (injected daily for 5 days) on GSK-3ß phosphorylation. The summary data shows that all doses of lithium were found to increase GSK-3 phosphorylation. <b>B</b>) Representative western blots and summary data showing that the different doses of lithium had no effect on the total levels of GSK-3ß. <b>C</b>) Representative western blots and summary data showing that lithium administration causes a significant accumulation of ß-Catenin, with maximal levels seen at the 1.0 mEq dose. <b>D</b>) Representative western blots and summary data showing that a single dose of 1.0 mEq/Kg lithium has no effect on the phosphorylation or total levels of GSK-3ß, nor on ß-Catenin accumulation. Data are presented as the mean ± SEM. *, P≤0.05 by one-way ANOVA compared to vehicle (0 dose) injected animals. n = 3/group</p

Post-TBI lithium administration has no effect on motor function, but exacerbates post-injury weight loss.

<p><b>A</b>) Schematic of the injection and behavioral testing paradigm. Injured rats receiving 1 mEq/kg lithium (n = 10) performed similarly to vehicle-injected animals (n = 10) when tested for their <b>B</b>) balance beam performance, and <b>C</b>) ipsilateral and <b>D</b>) contralateral foot faults. <b>E</b>) Lithium exacerbated post-injury weight loss. Data are presented as the mean ± SEM. ≠, significant difference by repeated measures two-way ANOVA. *, P≤0.05.</p

Post-injury administration of lithium reduces hippocampal neuronal cell loss.

<p><b>A</b>) Representative photomicrographs of NeuN immunoreactivity from the dorsal, ipsilateral hippocampi of a vehicle- and a lithium-treated animal. Scale bar  = 500 µm. DG: dentate gyrus. The outlined area indicates the field in which the cell counts were carried out. <b>B</b>) High-magnification image showing NeuN immunoreactivity within the CA3 subfield from a vehicle- and a lithium-injected, injured animal. Scale bar  = 200 µm. Lithium treatment <b>C</b>) significantly reduced CA3 neuronal loss, but not <b>D</b>) cortical contusion volume after TBI. *, p≤0.05 by Student's t-test. Veh: vehicle; Li: lithium. Data are presented as the mean ± SEM.</p

SB-216763 inhibits the GSK-3 pathway.

<p><b>A</b>) Representative images of western blots for phospho-GSK-3ß, phospho-LRP6, phospho-ß-Catenin, phospho-Akt, and phospho-ERK in response to i.p. injection of SB-216763 (2.5 and 5.0 mg/kg) or vehicle (0 mg/kg) (n = 3/group). <b>B</b>) SB-216763 significantly increased the phosphorylation of GSK-3ß in a dose-dependent manner. The phosphorylation of the GSK-3 substrates <b>C</b>) LRP-6 and <b>D</b>) ß-Catenin, were found to be decreased following SB-216763 administration. The phosphorylation levels of <b>E</b>) Akt and <b>F</b>) ERK were unaffected by SB-216763 administration. Data are presented as the mean ± SEM. *, P<0.05 by one-way ANOVA.</p

TBI alters the regulation of GSK-3.

<p><b>A</b>) Schematic diagram showing the GSK-3 cascade. In the absence of Wnt signaling, GSK-3 complexes with APC, Axin, and casein kinase 1α (CK1a) and phosphorylates ß-Catenin (ß-cat) leading to its ubiquitination (Ub) and degradation. <b>B</b>) Upon Wnt binding to the Frizzled-LRP6 receptors, GSK-3 is translocated to the membrane via binding of Disheveled (Dsh) where it can phosphorylate LRP6, and allow for ß-Catenin accumulation and gene expression (via interaction with LEF/TCF transcription factors). <b>C</b>) Growth factor binding can result in Akt-mediated phosphorylation and inactivation of GSK-3. Rats (n = 5/time point) were subjected to TBI and hippocampi removed at various time points for western blot analysis. Representative images of western blots for <b>D</b>) phospho- and total LRP6, <b>F</b>) phospho- and total GSK-3ß, and <b>H</b>) phospho- and total ß-Catenin are shown. <b>E</b>) Summary data shows that TBI causes a transient increase in the phosphorylation of LRP6 on Ser¹⁴⁹⁰. <b>G</b>) The phosphorylation of GSK-3ß on Ser⁹ is increased in a delayed manner, at a time point consistent with its phosphorylation by Akt. <b>I</b>) ß-Catenin phosphorylation was decreased at time points consistent with GSK-3 translocation to LRP6, but not as a result of GSK-3 phosphorylation. No change in ß-Catenin accumulation was observed. Data are presented as the mean ± SEM. *, P<0.05 by one-way ANOVA compared to sham animals.</p