HDAC9 and Alzheimer disease: Given the critical role of apoE as a key lipid transporting protein in the brain, its link to neurodegenerative diseases such as AD and traumatic brain injury, emerging role in diseases such as multiple sclerosis [58] and the importance of class I HDACs in AD, regulation of astrocytic apoE via pan class I HDAC inhibition could provide a novel mechanism for therapeutic intervention for several debilitating CNS diseases.