To further confirm that these HDAC6 inhibitors reduced fibrillar tau species, immunoblot analyses were conducted on the soluble and insoluble protein fractions from AD-tau-treated rat cortical neurons incubated with or without ACY-775 or ACY-1083 (at 6.7 μM, a nontoxic high dose). The gene discussed is HDAC6; the disease is Alzheimer disease.