Inhibition of histone deacetylation protects wildtype but not gelsolin-deficient mice from ischemic brain injury

Acetylation/deactylation of histones is an important mechanism to regulate gene expression and chromatin remodeling. We have previously demonstrated that the HDAC inhibitor trichostatin A (TSA) protects cortical neurons from oxygen/glucose deprivation in vitro which is mediated--at least in part--via the up regulation of gelsolin expression. Here, we demonstrate that TSA treatment dose-dependently enhances histone acetylation in brains of wildtype mice as evidenced by immunoblots of total brain lysates and immunocytochemical staining. Along with increased histone acetylation dose-dependent up regulation of gelsolin protein was observed. Levels of filamentous actin were largely decreased by TSA pre-treatment in brain of wildtype but not gelsolin-deficient mice. When exposed to 1 h filamentous occlusion of the middle cerebral artery followed by reperfusion TSA pre-treated wildtype mice developed significantly smaller cerebral lesion volumes and tended to have improved neurological deficit scores compared to vehicle-treated mice. These protective effects could not be explained by apparent changes in physiological parameters. In contrast to wildtype mice, TSA pre-treatment did not protect gelsolin-deficient mice against MCAo/reperfusion suggesting that enhanced gelsolin expression is an important mechanism by which TSA protects against ischemic brain injury. Our results suggest that HDAC inhibitors such as TSA are a promising therapeutic strategy for reducing brain injury following cerebral ischemia.