Development and characterization of novel anti-acetylated tau monoclonal antibodies to probe pathogenic tau species in Alzheimer's disease.

Tauopathies, including Alzheimer's disease (AD), are a class of neurodegenerative diseases characterized by the presence of insoluble tau inclusions. Tau phosphorylation has traditionally been viewed as the dominant post-translational modification (PTM) controlling tau function and pathogenesis in tauopathies. However, we and others have identified tau acetylation as a primary PTM regulating both normal tau function as well as abnormal pathogenic features including aggregation. Prior work showed robust tau acetylation in aggregation hotspots located within the 2nd and 3rd repeat regions of tau (residues K280 and K311) in tauopathy brains, including AD, compared to non-tauopathy controls. By screening thousands of hybridoma clones, we generated site-specific and modification-specific monoclonal antibodies targeting acetylated tau at residues K280 or K311. To validate these antibodies in a bona fide neuronal system, we targeted the acetyltransferase CBP to the cytoplasm of neurons to promote tau acetylation. Several antibody clones specifically detected CBP-acetylated tau and co-localized with ac-tau in neurons. Additionally, our lead optimal anti-acetylated-tau monoclonal antibodies detected robust tau pathology in tangles and neuritic plaques of human AD brains. Given the now emerging interest in acetylated tau as critical regulator of tau functions, these sensitive and highly specific tools will allow us to further unravel the tau PTM code and, importantly, could be deployed as diagnostic or disease-modifying agents.