Figure 6

HDAC3 activity contributes to inflammatory activation of microglia. (a–c) Experimental scheme, representative images of immunocytochemistry, and quantification show that LPS stimulation results in reduced AcH3 levels in primary microglia by 4 hr. Pre-exposure to RGFP966 reverses LPS-triggered AcH3 reduction. The numbers inside the bar graph indicate the numbers of cells quantified from nine photographs for each experimental condition. Mann Whitney test. **p = 0.0079, ***p < 0.001. (d–f) Experimental scheme, representative images of immunocytochemistry and quantification show that LPS stimulation decreases CD206+ population (green) and a trend of increase in iNOS+ population (red). RGFP966 pre-treatment reversed the LPS-induced bias, leading to increased CD206+ population and deceased iNOS+ population. DAPI for nuclear counterstaining. Arrow: examples of double positive (iNOS+ CD206+) cells. The numbers inside the bar graph indicate the numbers of images quantified. Mann Whitey test and unpaired Student’s t test, respectively. (g–i) Experimental scheme and quantification show HDAC3 knockdown by siRNA in primary microglia (unpaired Student’s t test). HDAC3 knockdown abolishes the polarized responses of microglia to LPS stimulation. The numbers inside the bar graph indicate the numbers of images quantified by Mann Whitney tests. Scale bar: 25 µm (a) and 50 µm (e).