FIG. 7.
Transgenic PRX2 overexpression inhibits the JNK signaling pathway after tMCAO. (A) Tg-PRX2 mice and their WT littermates were subjected to 60 min of tMCAO or sham operation. At 3 and 6 h after reperfusion, cortical tissue extracts were subjected to immunoblotting against p-MKK4, p-MKK7, p-JNK, and p-c-Jun or the total of each protein. Semi-quantitative data are illustrated in (B). Data are presented as mean±SEM, n=4–5 per group, *p<0.05, **p<0.01 versus WT mice. (C) Double-label immunofluoroscent staining for p-MKK4 (red, a–h and e′–h′) and NSE (green, e–h and e′–h′) in brain sections from Tg-PRX2 (c, d, g, h, low magnification; g′, h′, high magnification) or WT mice (a, b, e, f, low magnification; e′, f’, high magnification) with sham surgery or subjected to tMCAO and 6 h of reperfusion. Note that transgenic PRX2 expression attenuated ischemia-induced p-MKK4 immunofluorescence in ischemic neurons. Immunofluoroscent staining for p-c-Jun (red, i–l, low magnification) showed reduced p-c-Jun staining in Tg-PRX2 mice 6 h after tMCAO. Scale bars: low magnification, 50 μm; high magnification, 25 μm. (D-E) Attenuation of JNK activation mediates PRX2-afforded neuroprotection. JNK inhibitor SP600125 was administered before tMCAO or sham operation. At the dose of 10 mg/kg, SP600125 treatment abolished JNK activation at 3 and 6 h after reperfusion as demonstrated by immunoblotting against p-c-Jun. Determined at 48 h after tMCAO. SP600125 treatment significantly decreased infarct volume in WT mice, but failed to further reduce infarct volume in the Tg-PRX2H mice. Data are presented as mean±SEM, n=6 per group, *p<0.05 versus vehicle-treated WT mice; based on one-way ANOVA, followed by Bonferroni's/Dunn's post hoc analysis. (To see this illustration in color the reader is referred to the web version of this article at www.liebertonline.com/ars).