Figure 7.

Activation and expression of ASK1 in the macaque brain. (A) Active phospho-Thr845 ASK1 in macaque brain homogenates as observed by western blot analysis after immunoprecipitation of ASK1. The total levels of ASK1 immunoprecipitated for each animal also are shown. Determination of a ratio of phospho-ASK1 to total ASK1 for each animal from densitometric analysis of bands allowed for the comparison of relative levels of ASK1 activation between animals. Activation of ASK1 was observed in SIV-infected untreated animals, and this was significantly decreased by minocycline treatment (p = 0.004; Mann-Whitney test; results are the means of values obtained in duplicate blots). (B) ASK1 expression in white matter brain homogenate. By western blot analysis (performed in duplicate), there was no significant difference in relative ASK1 expression between any of the treatment groups (p > 0.05; Mann-Whitney tests). Using immunohistochemistry, total ASK1 expression was observed clearly in axons (C), as well as in astrocytes (as shown by colocalization with GFAP, D) in the subcortical white matter of all macaques, regardless of group. ASK1 expression also was observed in activated microglia and macrophages when they were detected in sites of inflammation (as shown by colocalization with CD68, E). Original magnification 200x.